Texture Shining through


I made a picture in Gimp to better illustrate my problem.

I have a static mesh that is instanced to make a roof.
The part of the texture on the lower side is black and the upper side is red.
If I am close to the mesh, there is no problem.
But if I zoom out, there are 3 black lines shining through the mesh.
First the middle line, that’s the border line where the instanced meshes are touching each other.
The other 2 lines are in the middle of the mesh and they show up later if I zoom out further.
I am doing a lot of instancing and never had a problem like that.
All other meshes wont behave like this.

Maybe, someone knows a way to fix this?

Thank you