I rebuilded light but results stay the same.
Does anybody know what is wrong?
If this make sense after rebuild the error occurs:
Instanced meshes don’t yet support unique static lighting for each LOD. Lighting on LOD 1+ may be incorrect unless lightmap UVs are the same for all LODs.
For me what solved it is painting one of the 2/7 particular Layers. Just painting with brush size set to around 32-64 or more with specifically these 2 materials (out of 7 I have) fixed the shade on the whole square/component.