A page or two back the question of traction roll, how to prevent it was asked. When all the "normal" things have been used and sudden flippage still rears it's foul head try these things.
1. Slow down that servo that makes the front wheels a blur.
2. Increase drag brake and reduce steering travel.
3. Soften servo saver. (ntc3s with stock servo saver will never traction roll)
4. Reduce front camber so the tyres cone out slightly.
5. SLOW DOWN IN A STRAIGHT LINE!