Runtime Mesh Component

having issue with using VertexColor of RMC.

The material applied is as simple as it can be. Using a Material with a fixed color, everything is fine. Using a Material that shows VertexColor, the RMC color differs.
Shadows are disabled to get rid of shadowing difference.

The Sphere is default static mesh from Unreal. The line is the RMC-Mesh.

Here is what I got with fixed color:

Using VertexColors. Material and colors are the same. Sphere does show the color wanted.
VertexColorBug_noVertexColor.pngVertexColorBug_VertexColor.png

The mesh is build via Blueprint CreateMeshSection/UpdateMeshSection.