Senario
A person has a permission to create a particular content only when he is a member of a particular group.
So if he is already a member of a group and request for another group he gets access denied error during the present session.
So he has to log out and again log in to get create the content.
tried the following patches
https://www.drupal.org/files/issues/og-field-access-audience-permission-...
https://www.drupal.org/files/og_subscribe_multiple_groups.patch

Didn't worked out