I am using Ubuntu 20.04.5 LTS (5.4.0-128-generic #144-Ubuntu SMP x86_64).
Yesterday after an apt update && apt upgrade, Firefox installed from apt install firefox in the past, started exhibiting this behaviour - No text displays, Font issue? - so I have reinstalled it from apt, not fixed, and then switched to the snap version which does work to some extent - no problems with normal browsing, but when running firefox using karma-firefox-launcher for an application test suite it is still broken.
firefox with borked font rendering
I would appreciate help into fixing this as nothing else on my system has been touched recently.
Edit: This also happens with Firefox from ppa: https://askubuntu.com/a/1404401
