Mobs that are on a different level or “floor” on the map still show up on the screen, quite a mess to look at.
Also, some of the trash mobs before the Aldus boss fight never enter combat.
HOTW bug/ glitch o.o
When did it start? There is a bug with the ‘sepia effect’ (yeah, seems like it’s part of an April’s fool joke) that causes nameplates to show up over obstacles.