I've been having a problem lately, even through the last few updates. My game and iPhone are completely up to date but this still happens:

My dwellers see ghosts. They say things about the corpses that are in the room with them, but nobody is dead in my vault.

This happens to most dwellers who go into two specific rooms. They start commenting about the corpse and their happiness goes down. One random dweller I've tried doesn't seem to see them (her happiness is still full). But even newly born dwellers see the corpses in these rooms. Once they leave the room, they don't see the corpse and their happiness goes back up slowly. So it must be the rooms. People have probably died in those rooms, but they were either revived or deleted. I repeat, no corpses in my vault.

Help! I don't want to have to delete and replace the rooms.

Thanks