tilix over X11 forwarded session - keymap wrong after during/attended upgrade

I'm inclined to think this is a bug, but I'd like to confirm that first.

During an attended upgrade (via do-release-upgrade) to 18.10, tilix stopped mapping keys properly over forwarded X11 sessions only. Tilix works fine on the console. The problem is that the keys no longer map to their constituent characters at all. Nothing maps correctly over the forward X11 terminal. Moreover, the problem started happening *during* the upgrade. I rebooted hoping that would fix the problem, however, it did not. The invalid keymapping persists over reboots meaning the same keys persist to the same wrong characters.

Some of the mapped keys to characters I have been able to determine are:

"e" -> bs
"4" -> "y"
"8" -> [enter]
"s" -> [tab]
"2" -> "r"
[caps lock] -> [space]
[left alt] -> [caps lock]

Note that prior to and even most of the way through the upgrade, the keymap was correct.

I'm not sure what I can give that is of much use other than:

$ dconf dump /com/gexperts/Tilix/
[/]
new-window-inherit-state=false
quake-height-percent=25
terminal-title-style='normal'
background-image-mode='center'
window-state=128
theme-variant='dark'
session-name='vmlinux'
new-instance-mode='new-session'
encodings=['UTF-8']
window-save-state=true
warn-vte-config-issue=false
quake-width-percent=55

[profiles/2b7c4080-0ddd-46c5-8f23-563fd3ba789d]
encoding='UTF-8'
foreground-color='#F8F8F2'
visible-name='vmlinux'
login-shell=true
palette=['#272822', '#F92672', '#A6E22E', '#F4BF75', '#66D9EF', '#AE81FF', '#A1EFE4', '#F8F8F2', '#75715E', '#F92672', '#A6E22E', '#F4BF75', '#66D9EF', '#AE81FF', '#A1EFE4', '#F9F8F5']
badge-color-set=false
default-size-rows=110
default-size-columns=180
cursor-colors-set=false
highlight-colors-set=false
use-theme-colors=false
bold-color-set=false
background-color='#272822'
background-transparency-percent=53
scrollback-lines=99999
jimconn@jimconn-vmlinux:~$ dpkg --list '*tilix*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-============================================================-===================================-===================================-=============================================================================================================================
ii tilix 1.7.7-1ubuntu2 amd64 Tiling terminal emulator for GNOME
ii tilix-common 1.7.7-1ubuntu2 all Tiling terminal emulator - data files

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic