Kalguur Iron + Blight = Blight unable to be completed

I have a map that has a Kalguuran Iron node and am doing blight. They spawned pretty close to each other. Close enough that when the blight tendrils went out, one of the portals that spawned, spawned right next to the central tower (the part that is usually interactable).

Monsters from that portal cannot leave. They have spawned, but I'm assuming there's some sort of "Can't be damaged until they get so far out from the portal" thing going on, because I cannot damage them.

As such this encounter will never finish.

See image:

https://imgur.com/a/OWgGFDo

Hi,
Had the same issue with a portal spawning on top of a Petrified Amber Tree on Beach map. Mobs unable to move forward.

Bug report #898,449,453

Image : https://imgur.com/a/bD1PgZZ