Not that I have much hope that this will get fixed, but at least the info is out there. There is another bugged rat in Tok's. This one is spawning behind the wall just past the exit from the Pacman puzzle. I've gone up and down this hallway several times thinking I keep missing it somehow, but no, its behind the wall.
[BUG] Tok's Proving Grounds rat spawn(s).-2019-03-13_161608.jpg

Just to remind someone, the first one reported bugged is still spawning behind the south wall of the glass maze. Whether it's designed to spawn in the glass maze or the laser puzzle room, I'm not sure.