Can't edit any longer but just to clarify: That was on DuckDuckGo on Android, which is my one and only browser on mobile. So if something doesn't work with it, I disengage. Given this is HN, benefit of the doubt :)

Meaning now trying it on Desktop with Firefox and DuckDuckGo as an extension it works just fine.

On both, the FPS display is basically pegged at 60 FPS. So I think this is probably technologically awesome work for the performance side and just isn't compatible with some specific setup(s).