yeah, maybe a nitrous shot cracked your piston or bent the rod on a detonation. Maybe you used it with the car too hot...and didnt notice.
The cracked piston will not hold pressure for long from the cracks as time goes by, it will begin to push the cracked part down and compression will be lost. Car will stumble, like no power when launching the car. Oil will go up the piston and some pressure released inside the block.