I think its more of a flexing issue. Your horse needs to go back to basics on the ground & learn to flex more, maybe even give lightly to the bit. Yes your horse may be
WELL trained but sometimes they do have holes in the foundation that
NEED to be taken care of. Its
NOTHING to do with what you ride them with, you could ride in just a halter & get sharp good turns with a lead rope attached to the links in the halter if your horse flexes & gives well. See where im going with this?