multiplayer client de-synch

this is a weird one: the "arcorn spiral stairs" seems to induce multiplayer position de-synchronization for clients when they go throught it going upwards.
We ran into position de-synch in our base: client wouldn't be able to open or interact with furniture/chests (i some case it would interact with a different set) and host would see the player at a different position that the one they report to be at.
After a few tries, we found out that going up through the acorn spiral stairs would trigger the desynch. if we go upstairs using other ways, other stairs, jumping, etc..., the desynch wouldn't trigger. And such desynch did not triggerred anywhere else in the game.

Also, we found out that the black ant hill boss door and pond quick access to underwater dome are out of synch for clients: they appear closed for clients but opened for hosts and client can actually go through them.
No game breaking bugs though. position de-synch is a bit tiring but server seems to reconcile position after a few seconds