I had the same thing happen on mine during a counterclockwise,,, canopy facing me,, knife edge loop, except I stripped the right servo. Fortunately it was stripped bad enough that it just weather veined and i was able to fly in on 1 elevator half. Im using Futaba 9151 servos (128oz) and I thought my servo was too weak.
I got into the power too early on the downline side and I knew I was in a bad spot, sure enough I saw MEGA flutter and immediately got off the power made a 180 right turn and landed. I have since been very careful about high G maneuvers at relatively high speed.

I am saving up to replace with Hitec 5995MG servos. I GUARANTEE you I wont strip those babies.