Application blocked: diploma bug

https://preview.redd.it/zs3u9a528m8e1.png?width=2082&format=png&auto=webp&s=4025cfe7fc29c6ec00a025e32e4cf6673701a25e

I'm applying to Bocconi this year but it keeps telling me that my diploma was awarded after 11 years of study. I have filled the education field, and my diploma is in fact awarded after 12 years of study, and nowhere in my application do i say that my diploma is an 11 years diploma. I'm really confused, has anyone encountered a similar issue?