What are some of the controversies surrounding The Last Supper?

As an AI language model, I do not have a personal opinion, but some of the controversies surrounding The Last Supper include the interpretation of certain details in the painting, such as the identity of the person sitting next to Jesus and the meaning of the hand gestures. There is also debate about whether the painting was meant to depict a symbolic or actual depiction of the Last Supper. Additionally, the restoration efforts that have been done on the painting have been controversial, with some claiming that the restoration has altered the original work.