Operating system: Linux-4.15.0-58-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 960/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.40
Broken: version: 2.81 (sub 8), branch: master, commit date: 2019-09-06 22:44, hash: rBed779333bb82
Open this mb-lab.blend file in Blender 2.80 and last Blender 2.81/master:
In Blender 2.81 you can see artifacts in reflections like something related to some fresnel thing. You notice that artifacts change according to zoom or position when orbit view. This does not happen in Blender 2.80.
I'm not good with nodes, so I can't experiment much to better determine what the problem might be. Not sure if this is related to new shadows system.
The character was created with MB-Lab addon.