I just got this from Harris Cyclery:
"Hi Jay,
We found out that many of the IRDs are bad a couple days ago. IRD is sending us a new batch in a few days and I'll get one off to you as soon as they come in.
The problem appears to be the retaining ring on the pawls. During assembly it gets bent, then breaks, causing the pawls to move out of alignment.
Sorry for the problem. "