The setting "Advanced Shader Effects" makes all the mobs and summons black. Just all black. Well except the Cursed Man, which seems to blink madly from black to some crazy red/gold color over and over.
Both my PC and the wife's PC have the same issue, unticking this setting prevents the blackness from taking over the mobs.
General system specs:
PC#1 Ryzen 1300X@4gHz, 16GB ram, GTX 1050 Ti Phoenix
PC#2 Ryzen 1200@3.8gHz, 8GB ram, GTX 750 Ti (reference card)
Note: I've tried file repair, updating directX, reverting to older drivers, etc. None helped.