Comment by Anon_troll

I encountered similar trouble with both Firefox and Chrome on Ubuntu.

Based on a quick Firefox performance report on the minified source code, most of the time seems to be spent in functionality looking like frame handling. There are some signs of time calculations.

One educated guess would be that something in frame time calculations goes off, possibly due to restricted time resolution to prevent timing related fingerprinting. This would cause next frame computation to start immediately instead of after the intended timeout.