Nameless Seer can spawn on top of boss arena portal

Was clearing a Temple map and the Nameless Seer spawned on top of the portal to the boss arena. He was slightly off-center, but close enough that he blocked me from physically being able to enter the portal.

I was able to make him disappear by taking a unique and scrying a map; however, that wouldn't have been possible if I wasn't willing to break the existing scry.

bug report reference number: 1519381205