I was doing 36 mugs 12 of the same design, two different design (24 mugs) perfect but the last 12 of a design that I never had a problem with before they were the last 12 mugs left to do, didn't notice till I moved them to shop where the light is much better they had a slight pink reddish hue on the white bits of the mug. Any idea what it could be. Its not the design as I have used it many times before. The best way to describe is a haze.f