Right, fixed.
So genius here just kept state in global variables which were, of course, shared between all connections. 🤦♂️
(So you were all just changing the same character, colour, mood settings but the updates were only getting sent to you so when someone else changed something, your character would reflect those changes too and appear to jump.)
Anyway, long story short, moved state to the session object and it should be good now.
Patch: https://codeberg.org/aral/kitten-kawaii/commit/fdb57e7794cc0c72f75a7273ac66b1514a667f0e