Immured Fury flew off the map

Reference: 2,270,617,005

So I was fighting the Immured Fury for the first time, I was fighting other monsters at the same time so not completely keeping my eye on them, but as far as I could tell, at some point it did a move that made it fly off, I would assume with the intent to come back with some big attack, but then it just never came back.

I'm actually able to go stand at the edge of the map and see its health bar, but it doesn't come to fight me.