Group invitation email

If an invited user get an invitation email to join a group with a link to accept (Accept Invitation Button) the link only works if the invited user is already logged in. Should the invitation link not work as well when the invited user is not logged in?

Here the link
.../index.php/en/component/easysocial/?controller=groups&task=respondInvitation&id=6&email=1&action=accept

Regards, Martin