This sounds like great advice, however I'd need a start as to how to fix such things. I've never placed in code before. Another question is how such things happen and what can be done to prevent them. I want to learn the issue so I can fix/prevent it in the future. Thanks
It's an issue with the binormal not being flipped when the UVs are. Fairly common issue with game engines. You can either try to fix it in the shader (I think UE4 does the transforms in the pixel shader anyway) or possibly in the mesh... although I suspect that would need some coding.
So I fixed this! When you import your normal map texture, make sure that you have it's Compression settings set to TC Normal Map. When imported it brings them in as TC Default, which is not for normal maps. Also make sure that in the material editor that the normal map node is a normal map node and not a default one, this…