I like to think that when Matthew started interfering with Will’s trial, Hannibal felt uneasy. He didn’t know who this other player that was throwing a wretch into Hannibal well laid plans was, especially because Will’s life was stake here. One wrong move = death penalty. I think when he went to stand witness for him, part of him was still mocking Will, but part of him was earnest in wanting to support Will. Of course he knew this flimsy evidence wouldn’t stand in court, he’s not stupid. But he’s selfishly taking Will’s side regardless, knowing it’s probably useless. A rare instance of acting mostly on emotion. But to Will, it must have entirely come across as Hannibal puppeteering him again. Laughing at him, playing with his food. Which is not wrong, yet Will doesn’t realise at this point that Hannibal runs deeper than his cruelty.