I don't think the OP was looking for advice on how to handle the room; they're reporting something that doesn't seem right. I agree that this sounds like a bug - if there are traps and you can use the disarm action and they appear to be successfully disarmed, they should actually be disarmed.
Yeah I should have read the OP post more thoroughly. My fault for following another commentor.
Agreed. That’s a bug. Once you disarm a head, it shouldn’t activate.