[1.5.5] Infinite Wrathroot

[Sinister Stairs]

My Old Forest 4 was generated with the Damp Cave, which I cleared before killing Wrathroot.

After killing Wrathroot, he respawns again every time I enter the Damp Cave (still cleared) and return to the Old Forest.

Wrathroot doesn't seem to respawn if I leave the zone via zone exits; only if enter returning via the Damp Cave. Also, when Wrathroot respawns, the map squares around his spawn point are dark, as if unvisited. He respawns with the same magical drops, but his artifact drop seems random.

I haven't tried entering the Damp Cave and exiting via Rod of Recall.

Possibly related, I've also had graves, demon status and pedestals infinitely re-usable (by exiting/re-entering the zone they spawned) in the Old Forest. It doesn't occur every game, but often enough I'm surprised when it doesn't occur.