This has only happened to me once so far, so this description is as accurate as I can get.

Me and a friend managed to acquire a punched card, and tried to get into the bunker on the southwest side of the map. We tried to use the secondary entrance, where there is a card reader on the top of the tower that opens a door on the bottom of the tower. When I activated the card reader with my (badly damaged) punched card, the punch card got degraded to ruined (as expected) and the sound of the door opening played as normal. However, the door at the bottom of the tower (which we triple-checked to see if it was indeed the right door) did not open. My friend also tried to open the door manually within 2 seconds of the sound effect playing, which did not work as the door still seemed locked. 10 seconds after I activated the card reader, the door closing sound effect played, with again no sound effect.