kamikaze reweighting + parton shower

Dear experts,
I am using Kamikaze reweighting for EWKdim6NLO model. I generate a QCD NLO sample with aMC@NLO (0,1 jet), get the lhe file, and then I run the reweighting that adds additional weights into existing lhe file.
My problem is when I try to run fxfx matching pythia8 on the output. I run pythia outside of MG framework. If I start from lhe file before the reweighting the fxfx pythia8 matching runs fine, matching efficiency is ~50%. But if I start from lhe file after reweighting then the matching efficiency is 0.
I notice that when I do the reweighting there are other small changes in the lhe file on top of just adding extra weights for each event. For example:

before reweighting the line in lhe file:
<event npLO=' -1 ' npNLO=' 0 '>

after reweighting the line becomes:
<event>

Here is a ship of event before reweighitng:
----------------------------------------->
  <init>
   2212 2212 0.65000000E+04 0.65000000E+04 -1 -1 244600 244600 -4 2
 0.13912745E+01 0.45413123E-02 0.26872144E+01 0
 0.89207793E+00 0.31144248E-02 0.26872144E+01 1
  </init>
  <event npLO=' -1 ' npNLO=' 0 '>
  6 0 0.26872144E+01 0.18015476E+03 0.78186083E-02 0.11840000E+00
       -1 -1 0 0 0 501 0.00000000E+00 0.00000000E+00 0.79755649E+02 0.79756332E+02 0.33000000E+00 0.0000E+00 0.9000E+01
        2 -1 0 0 501 0 0.00000000E+00 0.00000000E+00 -.76154331E+03 0.76154338E+03 0.33000000E+00 0.0000E+00 0.9000E+01
       23 2 1 2 0 0 0.28105565E+02 -.47137718E+01 0.47827842E+02 0.10677752E+03 0.91114181E+02 0.0000E+00 0.0000E+00
       24 1 1 2 0 0 -.28105565E+02 0.47137718E+01 -.72961550E+03 0.73452220E+03 0.79824360E+02 0.0000E+00 0.9000E+01
      -11 1 3 3 0 0 0.21155049E+02 0.38765322E+01 0.74693435E+02 0.77728198E+02 0.51099893E-03 0.0000E+00 0.9000E+01
       11 1 3 3 0 0 0.69505159E+01 -.85903040E+01 -.26865593E+02 0.29049322E+02 0.51099893E-03 0.0000E+00 0.9000E+01
#aMCatNLO 1 0 0 1 2 0.11056197E+03 0.00000000E+00 9 0 0 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00
  <rwgt>
   <wgt id='1001'> 0.26872E+01 </wgt>
   <wgt id='1002'> 0.27017E+01 </wgt>
   <wgt id='1003'> 0.26468E+01 </wgt>
   <wgt id='1004'> 0.25993E+01 </wgt>
   <wgt id='1005'> 0.26149E+01 </wgt>
   <wgt id='1006'> 0.25586E+01 </wgt>
   <wgt id='1007'> 0.27964E+01 </wgt>
   <wgt id='1008'> 0.28095E+01 </wgt>
   <wgt id='1009'> 0.27564E+01 </wgt>
  </rwgt>
  </event>
<---------------------------------

after reweighting:
----------------------------------------->
<init>
2212 2212 0.65000000E+04 0.65000000E+04 -1 -1 244600 244600 -4 2
 0.13912745E+01 0.45413123E-02 0.26872144E+01 0
 0.89207793E+00 0.31144248E-02 0.26872144E+01 1
</init>
<event>
 6 0 +2.6872144e+00 1.80154760e+02 7.81860830e-03 1.18400000e-01
       -1 -1 0 0 0 501 +0.0000000000e+00 +0.0000000000e+00 +7.9755649000e+01 7.9756332000e+01 3.3000000000e-01 0.0000e+00 9.0000e+00
        2 -1 0 0 501 0 +0.0000000000e+00 +0.0000000000e+00 -7.6154331000e+02 7.6154338000e+02 3.3000000000e-01 0.0000e+00 9.0000e+00
       23 2 1 2 0 0 +2.8105565000e+01 -4.7137718000e+00 +4.7827842000e+01 1.0677752000e+02 9.1114181000e+01 0.0000e+00 0.0000e+00
       24 1 1 2 0 0 -2.8105565000e+01 +4.7137718000e+00 -7.2961550000e+02 7.3452220000e+02 7.9824360000e+01 0.0000e+00 9.0000e+00
      -11 1 3 3 0 0 +2.1155049000e+01 +3.8765322000e+00 +7.4693435000e+01 7.7728198000e+01 5.1099893000e-04 0.0000e+00 9.0000e+00
       11 1 3 3 0 0 +6.9505159000e+00 -8.5903040000e+00 -2.6865593000e+01 2.9049322000e+01 5.1099893000e-04 0.0000e+00 9.0000e+00
#amcatnlo 1 0 0 1 2 0.11056197e+03 0.00000000e+00 9 0 0 0.00000000e+00 0.00000000e+00 0.00000000e+00 0.00000000e+00 0.00000000e+00
<rwgt>
<wgt id='1001'> +2.6872000e+00 </wgt>
<wgt id='1002'> +2.7017000e+00 </wgt>
<wgt id='1003'> +2.6468000e+00 </wgt>
<wgt id='1004'> +2.5993000e+00 </wgt>
<wgt id='1005'> +2.6149000e+00 </wgt>
<wgt id='1006'> +2.5586000e+00 </wgt>
<wgt id='1007'> +2.7964000e+00 </wgt>
<wgt id='1008'> +2.8095000e+00 </wgt>
<wgt id='1009'> +2.7564000e+00 </wgt>
<wgt id='mg_reweight_1'> +2.6840847e+00 </wgt>
<wgt id='mg_reweight_2'> +2.7235047e+00 </wgt>
<wgt id='mg_reweight_3'> +2.6832529e+00 </wgt>
</rwgt>
</event>
<---------------------------------

I did not notice any important difference in the header of lhe...
Is the zero matching efficiency in pythia8 expected and related to these changes in lhe?
Thank you in advance!

Greetings,
Senka