V3.0.5, tested on v3.1.0 as well
Hi. I love the new unsubscribe button. It doesn't unsubscribe me from an issue though. After I click on the unsubscribe button, the issue disappears as I would expect, but if there's new activity on the issue it appears in Gitify again as if I did nothing. If I look at an issue I've unsubscribed from in Gitify, Github's button still indicates I can unsubscribe (indicating I'm still subscribed).
I've logged out of Gitify and re-authenticated, but it still have the issue.
I'm on Mac/Catalina 10.15.5