I am trying to simulate a paper folding (1st photo) using cluster deformer and I was able to make a kite base (2nd photo) with no problem. Everything works fine up to this point (I am using double side shaders). Here I only fold the paper by 179 degrees rotation in order to avoid the overlapping. Also edges are all hardened.

Then I was trying to fold the base in half vertically and I noticed that the front sided shader smeared into the back (3rd photo). I was experimenting with 1st fold rotation between 179 and 179.9 degrees and the results are the same.

If you have experienced this kind of problem, I would appreciate your comments. Thank