We recently discovered an issue with our animations where the arms' normal map would break when applying animations. These animations are made in Blender. In Blender the arms are scaled by the rig/armature and not by scaling the mesh.

When imported and applied in-engine, this is the result: http://i.imgur.com/pwqWA4G.png

To troubleshoot I removed all scaling on the arms rig and it fixed it. This was the result: http://i.imgur.com/3s51PkL.png

I had found this thread and we have tried the hack posted here but to no avail.

For what it's worth, we had a previous arms mesh that did not have these issues. We had a new hands mesh made to the same dimensions as the old hands and re-skinned them to fix the rig. In Blender I see no issues.

The problem with this is I will have to go through and re-animate all of the animations which is hours upon hours of work if we need to switch to the un-scaled arms.

If anyone could help it would be EXTREMELY appreciated and would save my team and I many hours and headache.