Nah, I think after Luffy awakened and started to seriously fight and push luffy, there's no reason for him to say "Haki conquers all" if he is using an awakening form as an Ace.
The best explanation would be if Kaido doesn't have control over his awakening and can't consciously use it.
The best explanation would be if Kaido doesn't have control over his awakening and can't consciously use it.