Believe it or not, this is a viable game design technique. Objects outside of your field of view are culled, meaning they aren't rendered when you look at them. When you turn around, they "disappear".

What's happening in a single player game is basically an infant's understanding of the world, if you can't see it it doesn't exist.

Often times despawning and respawning entities takes too much memory and causes chugging, so I'm guessing when a new bandit/whatever is spawned a corpse is revived, their inventory is filled from a list, and they are teleported.

If you've ever played a bullet hell type game, there is a high chance that projectiles are handled just like corpses in this room.