Currently when a player enters a map, almost every object (moveables/doors, triggers, timers, decors, etc) will be in their default locations or settings.
This is normally not an issue but it's a big issue for doors/moveables as you can have a player in a moving helicopter/floating platform made out of moveable blocks and the player joining the map will only see a floating player as the moveable blocks will be in their default location.
The same can be said about a door that is open by default, a player closes that door, and the new player "clipping" through that closed door as the door is open on their screen.
This tends to lead to unfair situations, weird experiences, or map ideas not being possible.
It can be a map editor option to make objects update but at least the moveables should update their positions.