With glib2.0 2.75.3-3 installed and when starting the Firefox snap from terminal I see these warning messages:
[Parent 3792, Main Thread] WARNING: Unable to connect to ibus: Could not connect: Permission denied: 'glib warning', file /build/firefox/parts/firefox/build/toolkit/xre/nsSigHandlers.cpp:167
(firefox:3792): IBUS-WARNING **: 15:23:11.814: Unable to connect to ibus: Could not connect: Permission denied
With glib2.0 2.75.3-3 installed and when starting the Firefox snap from terminal I see these warning messages:
[Parent 3792, Main Thread] WARNING: Unable to connect to ibus: Could not connect: Permission denied: 'glib warning', file /build/ firefox/ parts/firefox/ build/toolkit/ xre/nsSigHandle rs.cpp: 167
(firefox:3792): IBUS-WARNING **: 15:23:11.814: Unable to connect to ibus: Could not connect: Permission denied
FTR the issue is present on both wayland and x11.