Issue on Nudity/Sexual Activity class

We discovered an issue on Moderation's classes in Amazon Rekognition while scanning a lot of social network content. A lot of selfies are tagged as Sexual Content / Activity or Nudity with a very high confidence score (97-99%). The pictures are not ambiguous, for instance it happens a lot on selfies with Moisturizing face mask (example: https://i.pinimg.com/736x/bd/bd/0f/bdbd0f00a8b661c3e5a7b5cf7fa5023f.jpg). But it happens too on random pictures, for instance a group of young girls taking a picture at a train station. Do you have any insights about that? It would help us a lot.