Invitation to a private groups makes page load twice

When a user visits a invitation-link to a private group, the page loads twice.

1) OG config: see attach 1
2) group config: see attach 2
3) result when user visits link supplied in invitation-mail: attach 3
4) after clikcing subscribe in the bottom of the window, the user is presented with access-denied. No message that the subscription will be evaluated by the group-admin