Perhaps the engine is not really shutting down. It may be that the time the engine takes to get back running is proportional to the time or severity of the negative Gs you are pulling.
Im just thinking of when pulling extreme and extended positve Gs, you black out for longer. Sometimes I have had a completely black screen for ten seconds! (no my pilot wasnt wounded. I'll point out that this has happened after i have released all pressure on the stick.
So maybe this egine cut out is the same thing. Next time it happens (when your engine seems totally dead,) just try waiting. Worse thing that could happen is you hit the ground and you have to re-up.
And no use trying to recreate this problem you experience. You know bugs never occur when you want them too.
