I had meetings near Olympia today so I took my upper & broken bolt with me and stopped by the J&S Shop.
They already had a replacement bolt in for me AND checked my chamber to ensure there were no issues.
All in all, Great customer service from guys who build really accurate rifles!
The guy behind the counter did tell me that mine was the 6th broken WilTec bolt they'd seen in the last 2 years and all of them were sold in 2010. This lines up with the same reports I've seen on other sites and confirms my suspicion that a batch released in 2010 had improper heat treating.