Having just sent out a whole slew of invitations, I’ve seen this happen a few times now. People accept the invitation with one username, but then change their mind. If I then follow the notification link, I get a 404 page. Ideally, this would redirect to the appropriate user’s page.
I’ve put this in as a bug because from a UX perspective, it feels buggy – the notification is right there, telling me about this user, but doesn’t work when I click on it. It was put in as a feature request before:
(I’m not 100% sure on the accepted etiquette here on meta. In composing this post, it suggested that as a possible duplicate, but when I went to reply to that post, it warned me that it was very old and perhaps not a good idea. Which is preferred?)