Playing Dragon Mound doesn't probably update the deck, should probably just show nothing, as the cards it think are in the deck, aren't there. Or maybe it could change into a tracking mode just as the how it tracks the opponent, as that would help keeping track of what can be revived from different cards.
In short, deck stays as it was when you played Dragon Mound, unless you draw a dragon that you actually had.
Playing Dragon Mound doesn't probably update the deck, should probably just show nothing, as the cards it think are in the deck, aren't there. Or maybe it could change into a tracking mode just as the how it tracks the opponent, as that would help keeping track of what can be revived from different cards.
In short, deck stays as it was when you played Dragon Mound, unless you draw a dragon that you actually had.