Lower mast bearing housing came loose. Torsional flex developed during tether flight; forward/aft has good transition. Lateral had a tendency to roll over...........shaft collar lock was too close to hub not allowing enough room to teeter. Some of the weight is too high up on the airframe as well. Lowering the motor and widening the lateral foot print of the lower airframe. Changing a few things, re-balance/track and try it again.
Dave