Breach creates invincible enemies

Sometimes breaches in maps create invincible enemies with no character models that follow you, can attack you, cannot be killed in any way, and if you get too far away from them they teleport either to you or to where the monster spawned. Sometimes doing the breach despawns them, sometimes it does not. I have some clips here demonstrating this.

https://www.twitch.tv/laurcus/clip/RepleteAgreeableYamJonCarnage-0KoF0Bv62aZKQ8pp

https://www.twitch.tv/laurcus/clip/ScrumptiousProductiveBaguetteFUNgineer-m-Im0w3kxccGmed5