Update: I called BUSA and left a message to inquire about the problem and status of the watch. An hour later, I got a call from my AD with the details (below). I guess they prefer to go through them on these things--oh well.
Apparently, there was a malfunction in the rotor system delivering power to the mainspring that caused the watch to intermittently stop. They are in the process of disassembling, replacing/fixing, and monitoring the watch now. I'm glad they figured out what was wrong and I guess I was just unlucky (the watch was bought less than six months ago). In any case, I can expect to have it back around my wrist in a few weeks and hopefully she'll be as good as new

Just curious: Anybody else who sent their watch in for service run into this problem too?