Bloated ... And not from beer

I fired a glaze load on the weekend and I finally got a look at the results on Tuesday. It appears that I have a case of bloating. Most, but not all of the pots look like they have small pox. This has never happened to me before. The only change that I made was to hold at top temp for 15 minutes, and the elements had just been replaced. I will fire again shortly and eliminate the hold and see if that solves the problem. I am not really impressed.