If your using Maya. Which it looks like it. I’ve had this issue also, and somewhere in the following steps it fixed it. I believe it was in close to this order. I had extra UV’s in my uv editor I had to delete. Then I went into hyper editor and manually re assigned materials. deleted all history. Saved scene. Shut down computer. Not restart.–This is sometimes extremely effective with Blender, and Autodesk.
Send to Unreal.
Then opened unreal engine, and clicked re import. It went away.