Nonsense...
First question, please explain how a gas charge that operates the recoil phase of the cycle of operation has any effect at all on the speed of the bolt group during the counter recoil phase.
Second question, given that top cartridge in the ammunition stack is resting against the bottom of the bolt group when the chambered round is fired, what action creates the force to displace the ammunition stack downward far enough to allow the bolt group to skip over said top cartridge.
oooops, had bolt override thought wrong. My bad.
Billdozer, definitely try another magazine to see if it still happens.