This is actually one of the disadvantages of bows with high letoff. There is so little tension on the string at full draw that any hand torque can be magnified. That's why your older Bear shoots beter for you---more holding weight. And it's one reason you will find a lot of the better shooters (especially target) shooting 65% letoff instead of 80%.

Can't say for sure how your form is, but one of the best ways to minimize this torque is to not grip the bow at all. Just let it sit on the meaty part of the thumb pad with a totally relaxed hand---not open hand---just totally relaxed with the hand turned out at about 45 degrees or so. When you release the bow your concentratiion should be on aiming and following through with the shot, letting the bow go through it's natural movement.

I suggest that if you belong to an archery club then you contact one of the better target archers to help with this and any other form flaws.