A few of my repositories have a public issue tracker with the option for anonymous issue creation. However, users are unable to create issues, and there is no "create issue" button on top-right of the site
I would also like to point out that this happens when I use a custom domain.
When I go to bitbucket.com/username/my-repository/issues I see the create issue button.
But when I go to mydomain.com/my-repository/issues, I don't see the create issue button.
This is a recent bug. Previously this worked as expected.
This only happens for guests. Users that are logged in can create issues irrespective of the domain.