Vaal Chest doesn't open in Expedition Range

Bug Report ID: #4265295551

The Vaal summoning circle happened to spawn within the confines of an expedition's markers, and did not open when the monsters were defeated. It did make the crystal activation sound and shows as completed on the map, but no chest came up.

Other details:
-Cleansed Map
-Extreme Archeology is allocated (tried to have the radius cover the whole Vaal area, but didn't seem to make a difference).
-There are lots of smoke wisps about the area, like it tends to do when it summons another wave of blood fanatics.