I had mine "pop out" of 2nd gear twice on an auto-x course. Both times it happened the anti-lock brakes were pulsating. I was braking with the wheels turned.
I have only had mine for a week, but I have noticed that when I downshift into second gear I feel the engine react (as if clutch is catching) even with the clutch fully depressed. Strange. I hope it does not develope into a problem. I know it is not kicking the gear out but second gear seems to be a bit different for some reason.
I went to Zoom-Zoom live last weekend and had that happen to me in 2 of the cars, while on the course, 2nd gear would pop out. the 2nd time that it happened it wouldn't go back in until I went into 1st and then 2nd.