I noticed the towel on the right hand side of the Hidrex has started to develop a hand print after my last session. The towel has become discolored where the 4 fingertips, thumb and part of the bottom of the palm rest when my hands are in the well. It's become kind of orange/brown, but only on the right side. Has this happened to anyone? I always wash my hands before starting a session so I know there was nothing on my hand.