This bug must be dependent on other choices/order in which events happen as, in my game, companion Gale met Mystra yesterday and the post-visit dialog was correct.
For you, was Gale repeating the Act 2 dialogue, ie had he already said it or had it somehow been skipped? In my game, I had already had the end of Act 2 dialog well before meeting Mystra.
Last edited by The Red Queen; 6 hours ago.