Originally Posted by Adam

I'd put money on it being torque on the string. When you're only holding 17-19 lbs at full draw it's very easy to torque the string, especially if you're missusing a back tension release.

There are really only 2 answers I believe. (1) swap to a thumb/ring-finger/little-finger release which will work better for you if you're having trouble with a BT release, or

(2) stick to the BT release but flatten-out your release hand. I'd guess that you shoot with the back of your hand flat against your face? We'll, if you draw-up the bow whist observing in a mirror (or get someone to video your draw hand), you'll be able to see a pronounced kink in the string between the d-loop knots when you press the back of your hand to your cheek. If you flatten out your hand (i.e. a bit more palm-down at full draw) you'll iron-out the kink, and find that the release will also go off more quickly (which may also help you to be consistent).

Adam