I already tested this. For me the error occurs on my Nvidia GTX 1080 as well as on my integrated Intel i5 8600k APU.
One Workaround I found in the meanwhile is using Xorg instead of Wayland.
@lendenu how can I check if this is happening for me as well? I suspect that it could have something to do with video playback, because the freezes seem to occur more frequently when playing videos but as described in Brad Smith’s Bug report, they also occur when just opening a tab, scrolling or switching to the Firefox windows from another one.