I couldn't reproduce in a Firefox fork in "troubleshoot" (safe) mode. Did reproduce in normal mode. It seemed to be somewhat mitigated by manually disabling extensions but then I couldn't pinpoint a config state to reliably reproduce it. Issue seems to return to some degree after clearing cache for the site. I didn't have time to finish doing this comprehensively but I think it isn't a clientside problem anyway. I'm not familiar with this SVG/Lottie animation but it seems that choppy/jerky/stuttering SVG animation with clip-path in Firefox is a known issue with a variety of workarounds floating around on SO, etc.
Mostly boring/useless but issue repro 1m38s https://www.youtube.com/watch?v=Z2erRvTeC3s