Double notifications for GitHub issues?

Am I the only one experiencing oddities for notifications in the GH issues that were migrated from Bugzilla?

For example, I was subscribed to LLVM Memory Model needs more rigor to avoid undesired optimization results · Issue #34577 · llvm/llvm-project · GitHub before the migration. When I checked a week ago I realized that (according to the “Subscribe”/“Unsubscribe” button GH shows) I am seemingly not subscribed to the GH issue. So I quickly subscribed (and searched for my name in the issue tracker to also subscribe to everything else where I used to be subscribed).

However, now I am getting two notifications for new messages in that issue! One is my regular GH notification emails, and the other one is sent to the email address that I had used in the LLVM bugzilla, which doesn’t even have a GH account. Where usually my name is in the email recipient address (Name <email>), it shows a UUID. I didn’t even know that is possible. It looks like the migration did know to put my GH username @RalfJung into the issue description, but somehow failed to subscribe that account and instead subscribed the (wrong) email address?

Is there any way that I can unsubscribe with that other email address to avoid the double-notifications? I cannot log in an unsubscribe since no account exists for that address…