As the topic says, NPC pathing is stuck in a loop. I had gone through a door, realized the NPC didn't, then when I went back inside to find them, the resulting video is what happened.
https://i.gyazo.com/a8365e394e682f41cf05abd999e0e90a.mp4
Playing on Excelsior. Specific mission is "Retrieve Dr. Pierce" from Buzzsaw.
EDIT: Entering/exiting the door a few times and getting into combat seemed to clear it out. Not entirely sure why, but it worked for the time being.