Question about paint feature ban

My friend and I were importing paints from Forza 5 and Forza Horizon 2 in order to work on getting the painting achievement. Essentially all of the paints we used were mostly matte black, had no writing or symbols and have been shared in both aforementioned games without any problems. A few minutes ago, we both received a message that we are banned for a week from the paint storefront and we were wondering what the issue is? To avoid future incidents like this, we just wanted to know if there might be a limit to paintjobs someone can share in a given amount of time, because to our knowledge that is the only thing that seems conceivable.

Thank you for your time.