Weird normals after applying baked normal map I created a sculpt, then retopologyzed it via Poly Build Tool and Shrinkwrap-Modifier. Now I'm trying to bake a normal map for the low-poly object but its really not looking like it should. The normal map looks ok to me, but every island of the uv-mesh looks totally diffrent in viewport and render. It looks to me a little like the normals were partially flipped, but I already recalculated them. So that should not be the problem, I guess. Maybe it is a Blender 2.8 problem. What do you think?
Here are some images:

Overlapping Objects

Normal map

The strange result of the normal map. Note that these are exactly the seams of my unwrap.

High-poly (left) and low-poly (right)

Material nodes
Thank you for your time! :)
Well, now it works. The only thing I did differently from the other times was to disconnect the Image Texture Node and changing the Color Space to Non-Color before the baking. I can't change the Color Space afterwards, this is new in Blender 2.8.