The fix can be viewed and tested at
https://codeberg.org/1peter10/mobile-config-firefox/commit/6ddb4b940d0bdda57822a6773222cc10ad3d173f
... my toughts (and in a way why this is not yet a merge request) can be found at https://gitlab.com/postmarketOS/mobile-config-firefox/-/issues/63#note_1826040361 .