Here is a difference , oh a slow one:
Conor does not just have a lisence. He already boxed. He's a professional boxer with a professional record.
Ali Act does not concern MMA. It talks specifically about boxing and Conor, for all intents and purposes, under its jurisdiction.
Boxing lisence does not void UFC contract. But it will make a huge collison between two official papers, which will likely get to the court.
However, Ali Act, FEDERAL document (unlike UFC contract) states that the company cannot prevent boxer from boxing.
And that will make UFC contract very, very problematic, if not illegal, in this case.