Comment # 1 on bug 1036342 from Vasilis Liaskovitis

Can you share the gnome-session coredump backtrace? If coredumpctl is enabled,
"coredumpctl list" should show the core dumps generated, and "coredumpctl gdb
PID" should be able to give you the backtrace. Some debuginfo packages may need
to be installed for symbol info.

Is wayland enabled (i think it should be on by default in recent TW) or is this
an Xorg session? Is gnome-session-wayland installed?

I can't reproduce this on an updated TW. But I think I have seen a
gnome-session fail/retry loop in the past when doing "systemctl restart
display-manager.service". But restarting the display-manager has other problems
currently for me (gnome-shell segfaults (bsc#1036432), or input-device problems
/screen tearing)