So, took it back and had the pads removed and inspected. There was a very odd wear pattern already present in the pads, something the LBS guy had never seen before. We called Avid, we were all stumped, he put new pads in under warranty and the problem is gone! I wish I had a picture, but it looked like the mark of the tip of an iron when it burns something...bizarre! I'm just glad to be riding the Poprad again. My poor Serotta is wondering where is my master?!