Are you referring to the ones with excessive sandbox permissions that flathub allows by default? Or is this something else?
Do you have a work profile or multiple user profiles set up on your device? This is similar to another issues they had a couple months ago, where my phone would fail to boot even into recovery to try to factory reset it.
I just use the Firefox flatpak from flathub.
Definitely a strange choice for a distro that pushes flatpak to not use it for the browser by default.