Updated map. Previously, I could not reproduce the stair bug, but now it's included.

It seems to be caused when the upper stairwell borders a rooftop and moving between floors. The game treats this as if the player is on the roof. When not wearing a disguise during the day, guard heat rises because the sniper towers see you. This is supported when, at 80+ guard heat, triggering the bug also triggers the gun sound.

However despite figuring all this out and (seemingly) removing the problem from one of my other maps, a new one I'm working on still has the problem despite me making sure the upper stairwells are completely enclosed. This time, having the area behind the lower stairwell marked as "illegal" (as in a part of the guard barracks or a similar zone) seemed to trigger it.

That said, during a recent test run, the bug appeared on some stairs, but not others, and then mysteriously vanished altogether. It seems the only thing I learned with this bug was how to reproduce it successfully, but my "fix" has yet to be 100 percent certain.

Also updated the bug discussion tab to include some recent discoveries, such as Ghost NPCs and Robinson replacing prisoners in a reloaded save.

Updated to include a demonstration of effective camera range. This time, I'm not actually sure if this is a bug or intended, but apparently while a camera can spot you fighting, looting, standing on desks, or just being where you shouldn't up to 8 tiles away from the camera, their ability to see you breaking walls or cutting fences is less than half that for some reason.

Originally posted by Ozoneraxi:

Job officers noclip through normal doors instead of opening em in custom maps. You can add that too.

That might fall under "ghost npcs."

I added it to the map. Thank you for bringing it to my attention.

Updated the map again to add some minor visual clarity to the camera range and wall chipping bugs, as well as seal off all possible exit routes not only to show how easy it is to get away with making a truly inescapable prison, but the green door bug still causes the editor to warn me that the prison is easy to escape.