Hi All We have a "new to us" refurbished Surge Belly milker that I am using on our Brown Swiss. Yesterday was the first milking with it and all went well except when I pulled the milker off one front teat was PURPLE!!! She was also not happy about me stripping it. It stripped clean and within a half hour was back to normal. Again today the same thing happened when I removed the milker. PLEASE HELP WHY AM I GETTING A PURPLE TEAT????