So looking at a random nonsense spam post - someone the signed up did passed all measures.

Yet it doesn't show who approve the moderated post as someone in the Curious group their content must be moderated. Once they make a post

they are then granted access to the Newbie group who also have content moderated < 3 posts?  I looked at the moderation history it did not show who approved a post. - Is this event logged?

I want to know who approved the content, or if there is some bug in the Promoted by Group that is creating  a window that circumvents implied setting?

 

I don't think anyone manually approved.  It clearly says a Group Promotion rule auto promoted the user, so check that first.  

and the permissions for content for the Curious is: 

 

I think it would be also good to know in the logs if user utilized the post before registration or they registered approved then posted.

and the Newbie group has the same permissions requiring approval for content moderation.