Because Mythra and Did Mikhail and Mikhail pretend not to know each other in the base game?
I'm about to finish the Torna DLC and I don't understand why there's a difference between Jin or Malhos, or even Haze, who have a dialogue It makes it clear that they knew each other from Torna, but she doesn't even have a single line with Mikhail; in fact, I feel like Mikhail was talking about Mythra as if he had never seen her before.