shadows on faces with no source I'm getting some weird shadows on my mesh that I can't figure out how to remove. It appears they don't have any natural reason for being there as they are along straight edges and on  faces.

I've checked normals and they are all pointing the right way. I've removed double/unnecessary vertices. The mesh has 1x mirror and 1x EdgeSplit modifiers on, but applying these doesn't fix the problem. Iv'e tried change clipping without any luck.

The edges have been marked sharp, but removing this doesn't change the shadows. (The red dots are holes I made in the mesh with Boolean modifiers (that have been applied) and the back of the mesh showing through) The shadow problem was there prior to the boolean operation.





If I extend out a face the shadows are visible along the side/connecting face as well.



Hopefully someone can help me with this as it it driving me a bit mad at the moment.
Thanks.

Possible solution: It might have something to do with UV unwrap. Working to confirm if this is the case or not.

Blender 2.82a (Mac Catalina OS) Cycles render engine.
Figured out the problem (in this case) occurred due to UV unwrapping and an image texture that wasn't single colour. The UV unwrap crossed over parts of the image that was empty and created the black lines in seemingly random places. New UV unwrap and new image texture solved the problem.