Results of measuring timing chain stretch via cam phaser adaptation.

[old guy]

But wouldn’t more indexing cause the pawl to adjust to the new setting causing the clamp to lift and be more prone to fail?

I’d bet there is some correlation between when it fails and overall stretch but not enough data points to be sure

It only indexes out to accomodate for wear. It doesn't index back and forth. The problem occurs at start up. When oil pressure is applied to the tensioner it will move out to the tensioned position. This puts pressure on the metal clamp band. If it pops off the tensioner or the pawl fails it is no longer held in the proper position resulting in failure.