Me and my thrall were fighting the Watcher in the Unnamed City when it fell off it’s platform. The 1st time it teleported back up in a fairly quick amount of time. Then it happened again. This time it also teleported back up in a timely manner. However, the 3rd time it fell off it never teleported back up. So I climbed down and low and behold found it had respawned under its normal spawn point.
Enemies on platforms (not just archers) tend to fall down while attacking or getting knocked down.
It wouldn’t be a problem, but teleporting back, and not taking damage is more of an issue in my opinion.
My only suggestion to this boss that bring him closer to the middle where the junction is at the stairs.