If loosening and realigning the wedge doesn't work, I would try sanding down the stem up to the minimum insert line a bit. Did you buy the new for new or used? It could potentially have a smaller inner steerer diameter than your stem is designed for, despite your crown race fitting correctly, and a previous owner may not have known this was the case (a lot of old bikes were sold new with standard stems ground/milled/sanded down to fit French forks)