Transcendent Archer underground Bug

Map: Vaal Factory
Enemy: Transcendent Archer(?)(Not sure)
Type: Rare
Special: Duplicated from an Essence Rare

The enemy spawned Underground, but was still somehow able to go up and down stairs while still underneath the floor. Only the top half of the enemy was above ground.

I'm not too sure, but I think it was the duped rare for the map. The rare it was duped from was an essence trapped rare, so maybe a coincidence or not? The bugged enemy itself was not trapped, just to be clear.

https://imgur.com/a/bugged-poe-enemy-vgk9SOn

(Died getting the screenshots for these, I wasn't fast enough)