I don't know, it seems so unnecessary, and pretty embarrassing for GMC to post.These are sketches.... many for design studies... most never see the light of day.
Hardly news worthy to pick apart photoshops LOL
The whole purpose of this pic was just to find the rear design.
I can totally see how this would happen fairly innocently. The artist is looking for something to work off of so that they can knock something out quickly, and the social media person has no idea its not an original, so there's nothing really nefarious happening.
But GMC has updated their Instagram post and removed this pic, so I'm thinking they're not too happy about it.