Threads/posts created by guests are associated with user's account after registration but are marked as moderated. What could be the cause?
The product follows built-in forum moderation rules. Forum options "Moderate new threads posted in this forum" and "Moderate replies posted in this forum" will cause the content to remain moderated after posting and registration. Usergroup permission "Submit content without approval" for the usergroup "Unregistered / Unconfirmed" should also be set to "Yes" (default value) otherwise any content posted by guests will be forced to be moderated. "Spam management" options should be checked as well, as any rule triggering moderation of content posted by guests will cause the threads/posts awaiting moderation after the registration.