my 2 cents, had similar problem and after period of gradual improvement I hit a " wall" , almost like I started to regress. A pro gave me several possible reasons:
1. are you aiming with your dominant eye? do you close the other?
2. at lower light do you see hallow around your pins?
3. subconciously grabbing the bow at release (said here before re: torque), hold your bow up till you hear the arrow hit. I found bow sling very helpfull and it allowed " surprise" release.
4. punching the release trigger?
It is good to have somebody watch your form, many bad things we do subconciously.
Good luck with determining the cause.