I've never encountered such wear on any of my fingertip grips.

Hmm, the more I look at the pictures, the more it seems like overturning is the case. My hand accelerates and overtakes the ball, so my fingers are pulled out of the ball sideways and not straight (see picture).

I think doing this lots of times would make the depression just below the edge but leave the edge intact.

The last photo is of a ball that has 0" lateral and looks like the depression is a little less obvious, even though the ball has many more games on it than the ball in the first few photos. More right lateral pitch would make the fingers come out of the ball easier when overturning, right? Looks like everything points to overturning, so I guess it's really a release problem and has nothing to do with pitches?

The schematic below shows the ball as if it were looked at from the top, with the fingers being at 3 o'clock (for 90° axis rotation).

Next ball you drill try the following lateral pitches on your fingers or have your ball driller fill the fingers to the top of the hole with plug and redrill them with new pitches:

Assuming you're a right handed bowler

1/4 left on the middle, 1/2 right on the ring for your laterals, and depending on your flexibility anywhere from 1/8 away to 1/2 away on the fingers, the less flexible, the more away pitch. Personally, I use 1 inch away pitch on my fingers. Yes my fingers are that stiff.

OK, I'll try 1/4L and 1/2R and 1/8 reverse (my fingers are very flexible and I currently have 0 finger pitch).

Also, I think CoachJim just confirmed that I am overturning the ball in another thread, where he said that people have an inverted Track (exactly my case) if their fingers are coming out of the ball past the 3 o'clock position. So I guess the wear is really caused by the tip of my middle finger and is not a pitch problem.

Luksa, you said, "More right lateral pitch would make the fingers come out of the ball easier when overturning, right?"

If you are overturning, is this happening on other balls too? Overturning shouldn't be ball specific unless there is another problem with the ball, eg. pitch.

Yes, it's happening with all my balls.

I used to have a static release with the hand being at the 45° position behind and on the side of the ball. But then I started learning the active release (turning the hand from the back of the ball to the side). That's when my Track moved way lower. Only in the past few months has the Track moved closer to my fingers, but is still further away from the thumb. Obviously because I never stop turning the ball - I keep turning it until it leaves my fingers.

As I understand it now, a good active release is when you start on the inside of the ball, rotate to the back or slightly outside (depends on what AR you want) and then stop turning and go up through the ball. Correct?

I'm trying to learn a more load/unload type of release now, without as much sideways turning.

Yes, you are right.

"As I understand it now, a good active release is when you start on the inside of the ball, rotate to the back or slightly outside (depends on what AR you want) and then stop turning and go up through the ball. Correct?"

At presentation, if you rest your ball on your index finger, you will see where your fingers are, 7 and 8 o'clock. If you watch many pro backswings, they are on the inside of the ball, and come up through it to 4-5. Only a few go past there.