There has been a major avatar animator desync issue in large instances (60+ players). It seems quite random with who it affects, some players are not desynced (their animations/toggles/facetracking show just fine) and some players are in their default upload state.

To reproduce, join a very large instance and you'll notice several players in their default upload state, by asking around or recognizing friends' default avatar.

Players that are on the live build 1865, open-beta, and Unity 6 branch can see other players desynced AND they themselves can be affected by the desync.