Thanks @_Shaman & everyone who reported/assisted.
Several reports and infologs already enabled us to figure the cause for the current desync and a new build is being compiled as I'm posting this (ZK admins will probably apply it to the server soon after it's ready).
If desyncs persist afterwards, remember that infologs save lives, and more infologs save more lives.
EDIT: release is ready: 101.0.1-411-ga3bb590