Can anyone explain why i'm getting weird shading on my meshes in certain areas?

Hello,

I’m currently working on building my own environment and have been running into issues with some shadows on my meshes. This is my first time using UE4 so hopefully someone else has had this issue or it’s something simple I can fix.

I layed out the lightmap UVs in max and do not believe that to be the cause of this issue. What’s weird is if I rotate this mesh 180 degrees then the issues reverse. What was shading properly before is having the same odd shadow effect while the areas that had the issue before are fine. Has anyone ran into these issues before or know what the cause is? As you can see in the pictures I’ve only rotated the very bottom mesh, however the same issue applies to mesh above.

Thanks.