I found it a bit strange that Treasure Hunter is conditional on what the previous player did on his previous turn. It seems that especially in engine heavy games, it might be unclear how many cards the previous player gained on his previous turn, and if the player doesn't start with Treasure Hunter in his hand at the start of turn (so he doesn't realize he needs to keep track).
Is this the first/only card with this kind of dependency? How did you deal with it during the play-testing?
Smugglers from Seaside also cares about what the previous player gained.
In playtesting we kept track of how many cards the other player gained. It's usually a small number. You often have the Treasure Hunter in your hand already. And you know when your deck has a Treasure Hunter in it that you could potentially draw. Sometimes when you draw it mid-turn you weren't paying attention, but the other player usually knows how many cards they gained.