The flatpak has mesa 24.1.3 (so the same version I also had on the rootfs before I updated to 24.1.5 yesterday).
I found another difference between flatpak and the native Firefox instances, on about:support my native Firefox has HARDWARE_VIDEO_DECODING as “available”, while the flatpak it shows “Force disabled by gfxInfo” and “Blocklisted; failure code FEATURE_FAILURE_VIDEO_DECODING_TEST_FAILED”. Since I think it has something to do with the embedded videos on this website, it’s possible that it’s related to hardware decoding, which would explain why it doesn’t crash on the flatpak version without hardware decoding.
I did all my testing with native Wayland backend and no Xwayland (but I could test with Xwayland if needed).
Thanks for the link, that looks very similar to the problem I have. So I’ll wait for 24.1.6 to be released in a few days, or maybe I’m able to test the patch out tomorrow and see if the problem is fixed.
If 24.1.6 doesn’t fix it, I’ll create a separate new bugreport, but if this is already fixed in the next version there is no need to create more noise than needed 