Unwanted glitching when creating 3D spinning graphic

I can't figure out how to remove the glitching. It appears on both the image layer (top) and the solid color layer behind it, but only when it is facing the front, the back side is fine. The ony layer the glitching does not affect is the bottom solid color layer (the ribs of the coin). Does anyone know why it is doing this, and how to fix it? Thanks in advance.