Here's an update. MATE still crashes.
May 15 09:07:05 ourserver /usr/bin/x2gostartagent[11784]: successfully started X2Go Agent session with ID ouruser-67-1557925622_stDMATE_dp32
May 15 09:07:06 ourserver /usr/bin/x2goruncommand[12242]: launching session with Xsession-x2go mechanism, using STARTUP="mate-session"
May 15 09:07:06 ourserver /usr/bin/x2goruncommand[12243]: dbus wrapper available as /usr/bin/dbus-run-session
May 15 09:07:12 ourserver gnome-keyring-daemon[12586]: couldn't access control socket: /run/user/1201/keyring/control: No such file or directory
May 15 09:07:12 ourserver mate-session[12246]: WARNING: keycode1 not existent
May 15 09:07:12 ourserver mate-session[12246]: WARNING: keycode2 not existent
May 15 09:07:16 ourserver systemd[1561]: Starting Sound Service...
May 15 09:07:16 ourserver dbus-daemon[908]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.4752' (uid=1201 pid=12592 comm="/usr/libexec/mate-settings-daemon ")
May 15 09:07:16 ourserver systemd[1]: Starting Hostname Service...
May 15 09:07:17 ourserver dbus-daemon[908]: [system] Successfully activated service 'org.freedesktop.hostname1'
May 15 09:07:17 ourserver systemd[1]: Started Hostname Service.
May 15 09:07:19 ourserver kernel: traps: x2goagent[11774] trap divide error ip:55c9cc08ea1c sp:7ffe23323ec0 error:0 in nxagent[55c9cbfa0000+319000]
May 15 09:07:19 ourserver systemd[1]: Created slice system-systemd\x2dcoredump.slice.
May 15 09:07:19 ourserver systemd[1]: Started Process Core Dump (PID 12633/UID 0).
May 15 09:07:21 ourserver systemd-logind[1485]: Session 162 logged out. Waiting for processes to exit.
May 15 09:07:22 ourserver systemd-coredump[12634]: Process 11774 (x2goagent) of user 1201 dumped core. Stack trace of thread 11774:
#0 0x000055c9cc08ea1c XkbAdjustGroup (nxagent)
#1 0x000055c9cc08eaf5 XkbComputeDerivedState (nxagent)
#2 0x000055c9cc084ca6 ProcXkbLatchLockState (nxagent)
#3 0x000055c9cbfc0d18 Dispatch (nxagent)
#4 0x000055c9cbfa4821 main (nxagent)
#5 0x00007f8cd60cd413 __libc_start_main (libc.so.6)
#6 0x000055c9cbfa4b5e _start (nxagent)
May 15 09:07:25 ourserver abrt-server[12868]: Package 'nxagent' isn't signed with proper key
May 15 09:07:25 ourserver abrt-server[12868]: 'post-create' on '/var/spool/abrt/ccpp-2019-05-15-09:07:23.219326-11774' exited with 1
May 15 09:07:25 ourserver abrt-server[12868]: Deleting problem directory '/var/spool/abrt/ccpp-2019-05-15-09:07:23.219326-11774'
May 15 09:07:25 ourserver dbus-daemon[908]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.4792" (uid=1201 pid=12613 comm="/usr/bin/pulseaudio --daemonize=no ") interface="org.freedesktop.DBus.ObjectManager" member="GetManagedObjects" error name="(unset)" requested_reply="0" destination="org.bluez" (bus)
May 15 09:07:26 ourserver systemd[1561]: Started Sound Service.
May 15 09:07:26 ourserver pulseaudio[12613]: E: [pulseaudio] bluez5-util.c: GetManagedObjects() failed: org.freedesktop.DBus.Error.AccessDenied: Rejected send message, 2 matched rules; type="method_call", sender=":1.4792" (uid=1201 pid=12613 comm="/usr/bin/pulseaudio --daemonize=no ") interface="org.freedesktop.DBus.ObjectManager" member="GetManagedObjects" error name="(unset)" requested_reply="0" destination="org.bluez" (bus)
May 15 09:07:32 ourserver systemd-logind[1485]: Removed session 162.
May 15 09:09:12 ourserver systemd-logind[1485]: New session 163 of user ouruser.
May 15 09:09:12 ourserver systemd[1]: Started Session 163 of user ouruser.
May 15 09:09:21 ourserver /usr/bin/x2gostartagent[13428]: successfully started X2Go Agent session with ID ouruser-78-1557925759_stDKDE_dp32
May 15 09:09:22 ourserver /usr/bin/x2goruncommand[13822]: ERROR: command failed to execute
May 15 09:09:30 ourserver systemd-logind[1485]: Session 163 logged out. Waiting for processes to exit.
May 15 09:09:30 ourserver systemd-logind[1485]: Removed session 163.
May 15 09:10:13 ourserver systemd[1]: Starting system activity accounting tool...
May 15 09:10:13 ourserver systemd[1]: Started system activity accounting tool.
May 15 09:10:13 ourserver systemd-logind[1485]: New session 164 of user ouruser.
May 15 09:10:13 ourserver systemd[1]: Started Session 164 of user ouruser.
May 15 09:10:13 ourserver automount[1483]: add_host_addrs: hostname lookup for .cargo failed: No address associated with hostname
May 15 09:15:04 ourserver dbus-daemon[908]: [system] Activating via systemd: service name='net.reactivated.Fprint' unit='fprintd.service' requested by ':1.4832' (uid=0 pid=14472 comm="su - ")
May 15 09:15:04 ourserver systemd[1]: Starting Fingerprint Authentication Daemon...
gdb from the coredump:
Core was generated by `x2goagent -nolisten tcp -nolisten tcp -dpi 96 -D -auth /ouruser/.Xauthori'.
Program terminated with signal SIGFPE, Arithmetic exception.
#0 0x000055c9cc08ea1c in XkbAdjustGroup (group=<error reading variable: Division by zero>, ctrls=ctrls@entry=0x55c9cc8d1820) at xkbUtils.c:688
688 xkbUtils.c: No such file or directory.
(gdb) bt full
#0 0x000055c9cc08ea1c in XkbAdjustGroup (group=<error reading variable: Division by zero>, ctrls=ctrls@entry=0x55c9cc8d1820) at xkbUtils.c:688
act = 0
#1 0x000055c9cc08eaf5 in XkbComputeDerivedState (xkbi=0x55c9cc8e6c20) at xkbUtils.c:714
state = 0x55c9cc8e6c32
ctrls = 0x55c9cc8d1820
grp = <optimized out>
#2 0x000055c9cc084ca6 in ProcXkbLatchLockState (client=0x55c9ccc78500) at xkb.c:560
status = <optimized out>
dev = 0x55c9cc8b06c0
oldState = {group = 0 '\000', locked_group = 0 '\000', base_group = 0, latched_group = 0, mods = 0 '\000', base_mods = 0 '\000', latched_mods = 0 '\000',
locked_mods = 0 '\000', compat_state = 0 '\000', grab_mods = 0 '\000', compat_grab_mods = 0 '\000', lookup_mods = 0 '\000',
compat_lookup_mods = 0 '\000', ptr_buttons = 0}
newState = 0x55c9cc8e6c32
changed = <optimized out>
stuff = <optimized out>
#3 0x000055c9cbfc0d18 in Dispatch () at NXdispatch.c:482
clientReady = 0x55c9cc8cc070
result = <optimized out>
client = 0x55c9ccc78500
nready = <optimized out>
icheck = 0x55c9cc3ef6d0 <checkForInput>
start_tick = 0
currentDispatch = <optimized out>
#4 0x000055c9cbfa4821 in main (argc=15, argv=0x7ffe23324118, envp=<optimized out>) at main.c:353
i = <optimized out>
xauthfile = <optimized out>
alwaysCheckForInput = {0, 1}