Hard to diagnose much via the internet. Have you had your LBS look at things?
The rear brake could be a setup issue. On the previous bike it was possible to orient the cable clamp nut incorrectly and it would hang up on the brake booster. Eliminated that issue on the new bike, so not sure what's going on in your case.
On the bar, good idea to check the stem-to-fork bolts for proper torque. Likewise the stem pinch band bolt (the one that clamps the internal steerer), and even before that I'd loosen the pinch band bolt and ensure your internal steerer is properly set up. It preloads the headset bearings in addition to providing a mounting point for the stem.
Carl Matson
The rear brake could be a setup issue. On the previous bike it was possible to orient the cable clamp nut incorrectly and it would hang up on the brake booster. Eliminated that issue on the new bike, so not sure what's going on in your case.
On the bar, good idea to check the stem-to-fork bolts for proper torque. Likewise the stem pinch band bolt (the one that clamps the internal steerer), and even before that I'd loosen the pinch band bolt and ensure your internal steerer is properly set up. It preloads the headset bearings in addition to providing a mounting point for the stem.
Carl Matson