At some point, there was a change (as far as I am aware and in my own experience) that allowed ghosts to go through door transitions without opening doors. However:
Where: Any locked door that a character has a key to.
When: Activating a locked door.
What: When a ghost activates a locked door for which they have a key, the ghost will go through the transition, and the door will be left open.
As an aside, with this change, are ghosts now able to phase through any doors? If so, then it may also be a bug that a ghost cannot pass through locked doors for which they do *not* have a key.