Sometimes issues like this can also occur when you dupe an object and reverse it along a -x axiz or - z axis. When you freeze the transform Maya will warn you about negative faces. You need to go into the attribute Editor and turn off opposite. this will then cause the mesh to flip again and you'll need to again reverse the surface normals.
https://simplymaya.com/forum/showthre...=36625&page=11Interesting. Can you put up the link to the original thread? I'd like to have a read.
The first image is a simple cube where the left cube was created with using duplicate special with -1 across the x-axis.Also, I can't find 'opposite' in the attribute editor.