When enemies go to do their updated “pathfinding” in the Crucible and Jump up or over a chasm. They might be Stuck unable to go back, or keep going up and down ledges until you either hit them or wait for them to come to you.
This also sometimes causes, when attacked, the player character to plunge into the abyss.
And of course as soon as I started looking for the bug it never happens. But I did find a new instance of something similar. I hit it with a bomb and after trying to jump over it started this weird loop.