Not sure what changed about my release, I think it appears to roll better and is cleaner off my hand. Started getting that fun popping noise coming out of my Vise Vacu-grips that I didn't before though.

Anyone else get that too? Now that it's occurred consistently for the last two weeks, my mind has almost shifted to thinking if I don't hear it, I didn't get it off my hand as well.

Not too hung up on it, just something I'm noticing.

Is it like a vacuum pop? Like a kid putting his finger in his mouth and pulling it out side ways?

Most of the popping sounds I have heard from a bowlers release have come from the thumb creating a vacuum at release.

A thumb hole would have to be pretty tight and the thumb exiting at certain point/angle to create the sound. If a good release for you creates those conditions then it would be a sign of a better release.