In a group content add form, the og_group_ref is empty, except for the "_none" value This is only for non admin members. Administrators have the field populated, but logging in as anyone that isn't in that role produces an empty field, except for the "_none" value. 

I've tried adding the value manually, like this:

if(!isset($form['og_group_ref'][LANGUAGE_NONE][0]['default']['#options']['MyGroup'][$gid])){
  $form['og_group_ref'][LANGUAGE_NONE][0]['default']['#options']['MyGroup'][$gid] = 'current MyGroup';
}


This adds the item, but I get an error about an illegal option, so it's not the solution.

Again, the field loads all groups for the admin members, but not for non admins. Is there a special permission that needs to be set?
It turns out that organic groups permissions were inadvertently changed, causing the issue, and attempts to fixed this made it only worse. Permissions have been restored, and the system now works as expected.