Every time you stall, it is because something is holding you back. In your case, it is your left arm. So yes, this will hinder your progress, but in the same way that any weakness will. The way to overcome weakness is to train! So by pressing and benching, you'll make both arms stronger, as you already have done.
It may be that your left arm will catch up to the right arm, or the right arm may stay slighter stronger. In the latter case, by increasing the strength of both arms, you will be decreasing the percentage difference between the two. If you can press 2.5kg more with one arm than the other when your pressing 40kg, you might have a cause for concern. But if your pressing 100kg, who cares if there is a very small imbalance? Both arms are strong.