I had this happen multiple times now, where a flying enemy (one of the ghost guys in N'erud) spawned outside of the map and flew away, so even my AOEs couldn't hit him anymore, requiring me to give up the run.
#Enemies in bossrush spawning outside the map
formal turtle
spring rain
What Biome type was it? Tower or Underground? If the latter, there might be a fix
formal turtle
It was in an infected area, I dont think it was a tower
spring rain
It was in an infected area, I dont think it was a tower
If you stand in front of the exit, way of Kaeula and Spectral blade with Shocker can hit those below the ground
I'm almost certain I know which layout it was
If you need to actually find it first you can use hunter's first skill
formal turtle
It was too far out of the map to be hit tho
I did that
it was too far
also used big bang and worlds edge through walls, still didnt work
spring rain
That's weird
It should normally be coded to try and get to you, that's why they get stuck on the ramp near the exit
formal turtle
it spawned too far to get agro I guess
spring rain
Yeah, in that case you got hit by a super weird one
formal turtle
twice