A Dread Siphonist required for “The Curator empowered” step bugged out. I’m unsure of actions prior to the bug, but likely use of Misdirection and Multi-shot during attempt to initiate combat. Doesn’t aggro and can’t be killed due to evading.
Abandoned the quest and attempted to recreate the bug with Misdirection and Multi-shot for each pylon and was unsuccessful. Scenario completed without issue.