1.3.91 - Public, GOG, Windows 10. No mods, no DM Pro, nothing else.
Setup: A double door which is closed, but not locked (specifically - double thin door in Woodland tileset). An area activator which, upon crossing it, should close (deactivate) the door.
Party opens the door, goes through, triggers the area activator, which closes the door behind their backs.
What currently happens: the door closes, but only visually. Mechanically, it remains open - my party, enemies, projectiles, etc. can pass through it with no problems.
I've tested it with some other tilesets, Stronghold and Necropolis in particular, and the issue is present there, as well. Note that opening doors by area activators happens as expected, it's just the closing doesn't.