On other peoples screen doors are open and simply walk through the door that is closed on our screen and we have to open it.
PROOF at 02:36:55 - http://www.twitch.tv/sacriel/v/32647177
Notice how his friend just walks through a closed gate on his screen, and he has to open it after.
Idk what new door icons have to do with it, but this is a serious bug. I see closed doors, but my friend says they are open and he can walk trough them. Happened many times.
I can confirm this. Also if you enter a building through a door that appears open to you but closed to the server you cannot pick up items inside and any item dropped will appear outside as if your character was still standing in front of the closed door.