Not sure what you mean by ‘asymmetric’ but if you’re referring to air sometimes ‘leaking’ out one side compared to the other especially as you ascend in range… I experienced the same issue and then realized my front teeth are not even- that is one is a little more ‘recessed’ than the other. By altering the angle of the mouthpiece with my lips the issue was resolved. In other words the trumpet does not stick straight out from my face; it is slightly to the left which is where the recessed tooth is. Hypothetically if I were to get braces to correct the tooth alignment, the position of the trumpet likely would change. I also assume you are not referring to focal dystonia.