Mirage Blight Portal stuck on Petrified Amber Tree

Bug Report ID: #1,051,591,659

Within a mirage, when doing a blight encounter, one of the portals spawned on top of a nearby Petrified Amber Tree (that had already itself been completed).

All of the mobs that should come out of the portal are seemingly trapped unable to take a step out and have just piled up and are not yet targetable/damageable. There is a rank 4 firetower in range, as well as some rank 2 summoning towers. Neither they nor my character can do anything about the mobs.

This makes the blight encounter incompletable.