Is this a PCM reciever in your radio? Reason I ask is that in mine(Futaba) there is a feature that will lower throttle to idle for a brief amount of time when the flight-pack is low. This is designed as warning indicator of low-battery of radio.

When you say you snap-rolled it, and it went to idle, possibility I'm thinking is that using all servos for snap, it depleted the power enough to enable the "safety/warning" feature of your radio.

Just a thought here, it does sound like a power prob of sorts though, whether it be ignition or flight-pack. Good luck.