I don’t have an account on lemmy.studio, so I’m not able to run troubleshooting tests there myself.

I did do a test appointing my account from lemmy.ml as a mod to the test community, and that action federated immediately.

I’ve tried un-modding and re-modding your lemmy.studio account myself, but that also did not work.

I don’t think that having the same username is the problem because otherwise it would be a problem in both instances… But there could be a unique constraint. I will mod myself for a moment to test if my account shows the same problem.