I've noticed this a couple of times while soloing a danger room in T1. I'll be running around doing my bomberman impression and kiting guys in a circle. After a minute or two sometimes a gremlin will just wander into a corner and sit there staring at the wall. On one level there were 4 or 5 of them all just sitting there. They wouldn't react to me coming close, I could walk up to them, charge a bomb, drop it, and walk away. Hitting them with a bomb had a chance of waking them up, but sometimes they just went back to staring at the corner. Seems like an AI bug with the gremlins as I haven't seen anything else do it. It makes them trivially easy to kill. I might have a sceenshot on my laptop I could post later.
-Navis
Its because it was low on health. Its trying to run away but as there is no escape route so it just goes to the closest corner. Its sorta like sending a kid who peed its pants into corner.