This is the highest point of the ride, so it isn't a surprise that the ride would stall at the slowest portion of the ride.
Kevin (pkiknex) and I rode Flight of Fear a few years ago where the launch cut out. The train ground to a hault at the end of the launch, and required the staff to physically roll the train back into the station, as the roller coaster was built before folks had figured out to build launches at an incline to allow the train to naturally roll back.
At any rate, in talking to the ride ops, they said break downs were scant for the ride, and the launch would only under launch around 3 times a year. To my knowledge, this is the first Premier Spaghetti Bowl to stall.