Finally put Slick Willy up on an I59 Boost-Sustain motor.  Flown fist thing in the morning with no wind.  Weight on the pad was 3lb 8oz.  Motor came up to pressure quickly and the rocket cleared the rail smooth and straight.  Boost looked great until about 40 feet or so and then the rocket leaned over at about a 20-25 degree angle and started a long slow arcing profile for the remainder of the 7+ second burn.  I lost sight of it after burnout, but a couple of folks claimed to see the drogue event.  I would imagine it was moving pretty dang fast horizontally when the drogue charge went off.  My buddy Coops grabbed the tracker and jumped on his quad to hunt it down.  He found it on the west edge of the lakebed approximately 1.5 miles away.  Both the booster and upper payload sections had sustained minor zippers.  The upper section had seperated but the main chute was still inside.  It looks like when the drogue deployed the suden jerk also seperated the upper payload compartment pulling the main charge igniter with it.  I actually found the main charge intact inside the payload tube.  The igniter had been jerked right out of the powder container.  Besides the small zippers there was no other damage to the rocket and it should be back in action soon.  Still not sure why the boost went offline, but I will definitely think it through and fly this motor again.