Calculating normals using runtime mesh component function

I want to generate foliage on my procedurall terrain and I need to calculate normals to get proper foliage transform (rotation). I’am trying to generate normals using ‘Calculate Tangents for Mesh’ method in blueprint, aftering pressing play (and generating) my editor crashes with assertion fail problem (Assertion failed: UV0s && UV0s->Num() > CurrentPosition) (this class https://github.com/Koderz/RuntimeMeshComponent/blob/master/Source/RuntimeMeshComponent/Public/RuntimeMeshBuilder.h line 828).

I tried couple things: giving nothing to uvs array pin, giving array of vectors2d with size of vertices, giving array of vectors2d with size bigger than vertices array and still same problem. How can I fix it, or maybe you guys know better way of generating foliage on procedurall terrain at runtime?

I have the same problem, still no solution.