with my vx i can shoot in less than 20 degree weather all day. no ball breaks, no drop offs, original noid. i use the new militia lube, and upped the dwell two clicks to 14ms. always a good rule of thumb to up the dwell by a couple ms when below 40ish degrees F. sometimes you can have the sketchy issues because you just had enough dwell time to cycle the bolt through the thick lube not not enough to perform well.
battery, new lube, inspect / replace necessary o rings in reg and bolt system, up dwell to 14ms in cold weather 12ms in normal conditions, and possible noid replacement if the problems occur after all others do not fix the issues