Thanks for the test asset.
After looking at it I can see that the Normals are not aligned correctly which is causing lighting and shadowing issues.
Here’s the test asset original and corrected demonstration.
Once correcting the normals (which can be done inside UE4) everything checked out and worked as I would expect.
To fix the issue in UE4 do the following:
- Open the Static Mesh Editor
- Under the Build Settings enable “Recompute Normals”
- Hit Apply and then save the asset.
This will correctly align the normals to the faces. Right now they are a bit askew.
-Tim