Had to watch the end of the fifth round again. Liston stopped throwing his right in the sixth, but rewatching the fifth made me realize he stopped really throwing it in the fifth. In the fifth Ali complained his vision was impaired and Liston went after him. Towards the end of the round he stopped throwing his right. However, they said (and were rubbing) his left shoulder.
Not sure what to think but it seems like something fishy went on for this fight.