LHAPDF::MetadataError

I recently tried running madgraph with lhapdf in a cluster, and somehow it always end up with some error.
I also tried running systematics within madevent, but it also failed.
I'm not particularly sure whether this is a Madgraph-lhapdf problem or LHAPDF problem or a cluster problem. I apologize if I asked at the wrong place.

Regards,
Koay Yong Sheng

Previous command before running Madgraph were:
>setupATLAS
>lsetup "lcgenv -p LCG_96 x86_64-centos7-gcc8-opt madgraph5amc 2.7.2.atlas3"
>lsetup "lcgenv -p LCG_96 x86_64-centos7-gcc8-opt lhapdf 6.2.3"
>export LHAPDF_DATA_PATH=/cvmfs/sft.cern.ch/lcg/external/lhapdfsets/current/
>/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/bin/mg5_aMC

The following are the run_01_tag_1_debug.log file:
 #************************************************************
#* MadGraph5_aMC@NLO/MadEvent *
#* *
#* * * *
#* * * * * *
#* * * * * 5 * * * * *
#* * * * * *
#* * * *
#* *
#* *
#* VERSION 2.7.2 2020-03-17 *
#* *
#* The MadGraph5_aMC@NLO Development Team - Find us at *
#* https://server06.fynu.ucl.ac.be/projects/madgraph *
#* *
#************************************************************
#* *
#* Command File for MadEvent *
#* *
#* run as ./bin/madevent.py filename *
#* *
#************************************************************
generate_events run_01
Traceback (most recent call last):
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/extended_cmd.py", line 1515, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/extended_cmd.py", line 1464, in onecmd_orig
    return func(arg, **opt)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/madevent_interface.py", line 2469, in do_generate_events
    self.run_generate_events(switch_mode, args)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/common_run_interface.py", line 6963, in new_fct
    original_fct(obj, *args, **opts)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/madevent_interface.py", line 2511, in run_generate_events
    self.exec_cmd('refine %s' % nb_event, postcmd=False)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/extended_cmd.py", line 1544, in exec_cmd
    stop = Cmd.onecmd_orig(current_interface, line, **opt)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/extended_cmd.py", line 1464, in onecmd_orig
    return func(arg, **opt)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/interface/madevent_interface.py", line 3469, in do_refine
    x_improve.launch() # create the ajob for the refinment.
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/madevent/gen_ximprove.py", line 860, in launch
    main_dir=pjoin(self.cmd.me_dir,'SubProcesses')) #main_dir is for gridpack readonly mode
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/madevent/sum_html.py", line 747, in collect_result
    P_comb.add_results(os.path.basename(G), path, mfactors[G])
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/madevent/sum_html.py", line 425, in add_results
    oneresult.read_results(filepath)
  File "/cvmfs/sft.cern.ch/lcg/releases/MCGenerators/madgraph5amc/2.7.2.atlas3-e1369/x86_64-centos7-gcc8-opt/madgraph/madevent/sum_html.py", line 315, in read_results
    % (error_code, open(log).read())
Exception: Reported error: End code 134.0
 Full associated log:
==== LHAPDF6 USING DEFAULT-TYPE LHAGLUE INTERFACE ====
LHAPDF 6.2.3 loading /cvmfs/sft.cern.ch/lcg/external/lhapdfsets/current/PDF4LHC15_nlo_mc/PDF4LHC15_nlo_mc_0000.dat
PDF4LHC15_nlo_mc PDF set, member #0, version 1; LHAPDF ID = 90500
terminate called after throwing an instance of 'LHAPDF::MetadataError'
  what(): Metadata for key: Interpolator not found.

Program received signal SIGABRT: Process abort signal.

Backtrace for this error:
#0 0x2ae24d36a3af in ???
#1 0x2ae24d36a337 in ???
#2 0x2ae24d36ba27 in ???
#3 0x2ae24c475e62 in _ZN9__gnu_cxx27__verbose_terminate_handlerEv
 at /tmp/dkonst/build/contrib/gcc-8.3.0/src/gcc/8.3.0/libstdc++-v3/libsupc++/vterminate.cc:95
#4 0x2ae24c47bfd5 in _ZN10__cxxabiv111__terminateEPFvvE
 at /tmp/dkonst/build/contrib/gcc-8.3.0/src/gcc/8.3.0/libstdc++-v3/libsupc++/eh_terminate.cc:47
#5 0x2ae24c47c010 in _ZSt9terminatev
 at /tmp/dkonst/build/contrib/gcc-8.3.0/src/gcc/8.3.0/libstdc++-v3/libsupc++/eh_terminate.cc:57
#6 0x2ae24c47c243 in __cxa_throw
 at /tmp/dkonst/build/contrib/gcc-8.3.0/src/gcc/8.3.0/libstdc++-v3/libsupc++/eh_throw.cc:95
#7 0x493be7 in ???
#8 0x49e4b0 in ???
#9 0x4d59c6 in ???
#10 0x4a3c60 in ???
#11 0x48cfa8 in ???
#12 0x48d411 in ???
#13 0x484aac in ???
#14 0x482d23 in ???
#15 0x47f429 in ???
#16 0x414670 in ???
#17 0x415266 in ???
#18 0x2ae24d356504 in ???
#19 0x412da6 in ???
#20 0xffffffffffffffff in ???

ls status:
input_app.txt
run1_app.log

                              Run Options
                              -----------
               stdout_level : 20 (user set)

                         MadEvent Options
                         ----------------
     automatic_html_opening : False (user set)
        notification_center : True
          cluster_temp_path : None
             cluster_memory : None (user set)
               cluster_size : 100
              cluster_queue : None (user set)
                    nb_core : 56 (user set)
               cluster_time : 56 (user set)
                   run_mode : 2

                      Configuration Options
                      ---------------------
                text_editor : None
         cluster_local_path : None
      cluster_status_update : (600, 30)
               pythia8_path : None (user set)
                  hwpp_path : None (user set)
            pythia-pgs_path : None (user set)
                    td_path : None (user set)
               delphes_path : None (user set)
                thepeg_path : None (user set)
               cluster_type : condor
          madanalysis5_path : None (user set)
           cluster_nb_retry : 1
                 eps_viewer : None
                web_browser : None
               syscalc_path : /cvmfs/sft.cern.ch/lcg/releases/MCGenerators/syscalc/1.1.7-4bae8/x86_64-centos7-gcc8-opt (user set)
           madanalysis_path : None (user set)
                     lhapdf : /cvmfs/sft.cern.ch/lcg/releases/MCGenerators/lhapdf/6.2.3-752bc/x86_64-centos7-gcc8-opt/bin/lhapdf-config (user set)
              f2py_compiler : None
                 hepmc_path : None (user set)
         cluster_retry_wait : 300
           fortran_compiler : None
                auto_update : 7 (user set)
        exrootanalysis_path : None (user set)
                    timeout : 60
               cpp_compiler : None
#************************************************************
#* MadGraph5_aMC@NLO *
#* *
#* * * *
#* * * * * *
#* * * * * 5 * * * * *
#* * * * * *
#* * * *
#* *
#* *
#* VERSION 2.7.2 2020-03-17 *
#* *
#* The MadGraph5_aMC@NLO Development Team - Find us at *
#* https://server06.fynu.ucl.ac.be/projects/madgraph *
#* *
#************************************************************
#* *
#* Command File for MadGraph5_aMC@NLO *
#* *
#* run as ./bin/mg5_aMC filename *
#* *
#************************************************************
set default_unset_couplings 99
set group_subprocesses Auto
set ignore_six_quark_processes False
set loop_optimized_output True
set loop_color_flows False
set gauge unitary
set complex_mass_scheme False
set max_npoint_for_channel 0
import model sm
define p = g u c d s u~ c~ d~ s~
define j = g u c d s u~ c~ d~ s~
define l+ = e+ mu+
define l- = e- mu-
define vl = ve vm vt
define vl~ = ve~ vm~ vt~
generate p p > ta- ta+
launch
######################################################################
## PARAM_CARD AUTOMATICALY GENERATED BY MG5 FOLLOWING UFO MODEL ####
######################################################################
## ##
## Width set on Auto will be computed following the information ##
## present in the decay.py files of the model. ##
## See arXiv:1402.1178 for more details. ##
## ##
######################################################################

###################################
## INFORMATION FOR MASS
###################################
Block mass
    5 4.700000e+00 # MB
    6 1.725000e+02 # MT
   15 1.776820e+00 # MTA
   23 9.118760e+01 # MZ
   25 1.250000e+02 # MH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
  1 0.000000e+00 # d : 0.0
  2 0.000000e+00 # u : 0.0
  3 0.000000e+00 # s : 0.0
  4 0.000000e+00 # c : 0.0
  11 0.000000e+00 # e- : 0.0
  12 0.000000e+00 # ve : 0.0
  13 0.000000e+00 # mu- : 0.0
  14 0.000000e+00 # vm : 0.0
  16 0.000000e+00 # vt : 0.0
  21 0.000000e+00 # g : 0.0
  22 0.000000e+00 # a : 0.0
  24 8.039900e+01 # w+ : cmath.sqrt(MZ__exp__2/2. + cmath.sqrt(MZ__exp__4/4. - (aEW*cmath.pi*MZ__exp__2)/(Gf*sqrt__2)))

###################################
## INFORMATION FOR SMINPUTS
###################################
Block sminputs
    1 1.323489e+02 # aEWM1
    2 1.166370e-05 # Gf
    3 1.184000e-01 # aS

###################################
## INFORMATION FOR YUKAWA
###################################
Block yukawa
    5 4.700000e+00 # ymb
    6 1.725000e+02 # ymt
   15 1.777000e+00 # ymtau

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.320000e+00 # WT
DECAY 23 2.495200e+00 # WZ
DECAY 24 2.085000e+00 # WW
DECAY 25 6.382339e-03 # WH
## Dependent parameters, given by model restrictions.
## Those values should be edited following the
## analytical expression. MG5 ignores those values
## but they are important for interfacing the output of MG5
## to external program such as Pythia.
DECAY 1 0.000000e+00 # d : 0.0
DECAY 2 0.000000e+00 # u : 0.0
DECAY 3 0.000000e+00 # s : 0.0
DECAY 4 0.000000e+00 # c : 0.0
DECAY 5 0.000000e+00 # b : 0.0
DECAY 11 0.000000e+00 # e- : 0.0
DECAY 12 0.000000e+00 # ve : 0.0
DECAY 13 0.000000e+00 # mu- : 0.0
DECAY 14 0.000000e+00 # vm : 0.0
DECAY 15 0.000000e+00 # ta- : 0.0
DECAY 16 0.000000e+00 # vt : 0.0
DECAY 21 0.000000e+00 # g : 0.0
DECAY 22 0.000000e+00 # a : 0.0
#*********************************************************************
# MadGraph5_aMC@NLO *
# *
# run_card.dat MadEvent *
# *
# This file is used to set the parameters of the run. *
# *
# Some notation/conventions: *
# *
# Lines starting with a '# ' are info or comments *
# *
# mind the format: value = variable ! comment *
# *
# To display more options, you can type the command: *
# update full_run_card *
#*********************************************************************
#
#*********************************************************************
# Tag name for the run (one word) *
#*********************************************************************
  tag_1 = run_tag ! name of the run
#*********************************************************************
# Number of events and rnd seed *
# Warning: Do not generate more than 1M events in a single run *
#*********************************************************************
  10000 = nevents ! Number of unweighted events requested
  0 = iseed ! rnd seed (0=assigned automatically=default))
#*********************************************************************
# Collider type and energy *
# lpp: 0=No PDF, 1=proton, -1=antiproton, 2=photon from proton, *
# 3=photon from electron *
#*********************************************************************
  1 = lpp1 ! beam 1 type
  1 = lpp2 ! beam 2 type
  6500.0 = ebeam1 ! beam 1 total energy in GeV
  6500.0 = ebeam2 ! beam 2 total energy in GeV
# To see polarised beam options: type "update beam_pol"

#*********************************************************************
# PDF CHOICE: this automatically fixes also alpha_s and its evol. *
#*********************************************************************
  lhapdf = pdlabel ! PDF set
  90500 = lhaid ! if pdlabel=lhapdf, this is the lhapdf number
# To see heavy ion options: type "update ion_pdf"
#*********************************************************************
# Renormalization and factorization scales *
#*********************************************************************
  False = fixed_ren_scale ! if .true. use fixed ren scale
  False = fixed_fac_scale ! if .true. use fixed fac scale
  91.188 = scale ! fixed ren scale
  91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
  91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
  -1 = dynamical_scale_choice ! Choose one of the preselected dynamical choices
  1.0 = scalefact ! scale factor for event-by-event scales
#*********************************************************************
# Type and output format
#*********************************************************************
  False = gridpack !True = setting up the grid pack
  -1.0 = time_of_flight ! threshold (in mm) below which the invariant livetime is not written (-1 means not written)
  average = event_norm ! average/sum. Normalization of the weight in the LHEF
# To see MLM/CKKW merging options: type "update MLM" or "update CKKW"

#*********************************************************************
#
#*********************************************************************
# handling of the helicities:
# 0: sum over all helicities
# 1: importance sampling over helicities
#*********************************************************************
  0 = nhel ! using helicities importance sampling or not.
#*********************************************************************
# Generation bias, check the wiki page below for more information: *
# 'cp3.irmp.ucl.ac.be/projects/madgraph/wiki/LOEventGenerationBias' *
#*********************************************************************
  None = bias_module ! Bias type of bias, [None, ptj_bias, -custom_folder-]
  {} = bias_parameters ! Specifies the parameters of the module.
#
#*******************************
# Parton level cuts definition *
#*******************************
#
#
#*********************************************************************
# BW cutoff (M+/-bwcutoff*Gamma) ! Define on/off-shell for "$" and decay
#*********************************************************************
  15.0 = bwcutoff ! (M+/-bwcutoff*Gamma)
#*********************************************************************
# Standard Cuts *
#*********************************************************************
# Minimum and maximum pt's (for max, -1 means no cut) *
#*********************************************************************
  10.0 = ptl ! minimum pt for the charged leptons
  -1.0 = ptlmax ! maximum pt for the charged leptons
  {} = pt_min_pdg ! pt cut for other particles (use pdg code). Applied on particle and anti-particle
  {} = pt_max_pdg ! pt cut for other particles (syntax e.g. {6: 100, 25: 50})
#
# For display option for energy cut in the partonic center of mass frame type 'update ecut'
#
#*********************************************************************
# Maximum and minimum absolute rapidity (for max, -1 means no cut) *
#*********************************************************************
  2.5 = etal ! max rap for the charged leptons
  0.0 = etalmin ! main rap for the charged leptons
  {} = eta_min_pdg ! rap cut for other particles (use pdg code). Applied on particle and anti-particle
  {} = eta_max_pdg ! rap cut for other particles (syntax e.g. {6: 2.5, 23: 5})
#*********************************************************************
# Minimum and maximum DeltaR distance *
#*********************************************************************
  0.4 = drll ! min distance between leptons
  -1.0 = drllmax ! max distance between leptons
#*********************************************************************
# Minimum and maximum invariant mass for pairs *
#*********************************************************************
  0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
  -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
  {} = mxx_min_pdg ! min invariant mass of a pair of particles X/X~ (e.g. {6:250})
  {'default': False} = mxx_only_part_antipart ! if True the invariant mass is applied only
                       ! to pairs of particle/antiparticle and not to pairs of the same pdg codes.
 #*********************************************************************
 # Minimum and maximum invariant mass for all letpons *
 #*********************************************************************
  0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
  -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
 #*********************************************************************
 # Minimum and maximum pt for 4-momenta sum of leptons *
 #*********************************************************************
  0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
  -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
#*********************************************************************
# Inclusive cuts *
#*********************************************************************
  0.0 = xptl ! minimum pt for at least one charged lepton
 #*********************************************************************
 # Control the pt's of leptons sorted by pt *
 #*********************************************************************
  0.0 = ptl1min ! minimum pt for the leading lepton in pt
  0.0 = ptl2min ! minimum pt for the second lepton in pt
  -1.0 = ptl1max ! maximum pt for the leading lepton in pt
  -1.0 = ptl2max ! maximum pt for the second lepton in pt
#*********************************************************************
# maximal pdg code for quark to be considered as a light jet *
# (otherwise b cuts are applied) *
#*********************************************************************
  4 = maxjetflavor ! Maximum jet pdg code
#*********************************************************************
#
#*********************************************************************
# Store info for systematics studies *
# WARNING: Do not use for interference type of computation *
#*********************************************************************
  True = use_syst ! Enable systematics studies
#
  systematics = systematics_program ! none, systematics [python], SysCalc [depreceted, C++]
['--mur=0.5,1,2', '--muf=0.5,1,2', '--pdf=errorset'] = systematics_arguments ! see: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/Systematics#Systematicspythonmodule
# Syscalc is deprecated but to see the associate options type'update syscalc'#*********************************************************************
# Additional hidden parameters
#*********************************************************************
  ['--mur=0.5,1,2', '--muf=0.5,1,2', '--pdf=errorset'] = systematics_arguments # Choose the argment to pass to the systematics command. like --mur=0.25,1,4. Look at the help of the systematics function for more details.