So, what is this: Baiting the Amazon Snobs!?!?
First thing that came to mind is a Yellow-Faced Amazon (Amazona xanthops). Common in Eastern and Central Brazil region. If true this Amazon is very Rare, CITES, Class I for certain.
There is very little information available regarding them and what is does not speak well of their being very bright. Likely due to the only references was of a very young Amazon. If I was to guess, they are likely much like Lilac-Crowned Amazons, who also are not very bright as young Amazons, but become real lovers as they age.
The greatest problem with Amazons is that if you are not looking at a 'Nominate' of the species (Julio is a 9 out of 10 in that regard), they can really screw with your mind. Most Amazons under ten years of age have not fully settled on their coloration. Especially, this group of Amazons that provide a very wide presentation of colors. And yes, add the natural and forced hybrids and the World just turns upside down.
Those with all or part bone (clear) colour beaks are another area of conflict as it is not uncommon for the young to have variations with spots of black. The only exception to that is the DYH's, which are 100% bone (clear) coloured from day one! The dark coloured beaks do not change.
The joys of Species Classing Amazons!
*** That all said, and as Ellen has presented, a Cape Parrot, has possibilities as well.
FYI: Need more photos around the Amazon to better define!