Not, not any big ones, but I've seen a lot of Firefox specific bugs for smaller sites in the last 2 or 3 years. I've had to debug Firefox issues for my coworkers more than anything else. Sometimes Safari breaks too but that's important because of iOS. Firefox is only used by the ideologues and we don't bother officially supporting it anymore...

I found Amazon unstable on FF for a while a few years ago, it would randomly go off and spin the CPU or eat a pile of RAM, sometimes recovering and sometimes needing to be killed. It was one of the things that pushed me towards using Chrome more. Chrome has since started to have a few issues (occasionally dying and not remembering a chunk of my open tabs being the big recent one) so I'm starting to move back the other way ATM.

M$ teams web doesn't work in Firefox. I was forced to install Chromium under Kubuntu just to use teams at work, as I avoid to install the crappy full teams application like the plague, given it is proprietary, resource heavy and tries to auto-launch whenever it can.