My 2007 Passat was protected with Z2 initially and then I switched to DG105. In all that time I never had one water spot on the car. In May I polished with Speed and then added a coat of POXY the next morning. Over the past week we've had some heavy showers followed by full sun. For the first time in six years I now have a few water spots or etching--tried to remove them by hand with some ZAIO--it lessened them, but didn't take them out completely. Anyone else noticed this with POXY??