On a Possession turn, during the resolution of Butcher, the coin tokens are correctly given to the possessing player. Then, that player is given an option to trash a card and gain another. The bug occurs when the gained card is selected. Coin tokens are not deducted from the possessed player as they should be.
A possesses B. B has 2 coin tokens left over from a previous turn.
B (possessed) plays Butcher. The 2 coin tokens go to A.
B (possessed) trashes Gold and is given the option to gain a card costing up to $8 (the cost of Gold plus the 2 tokens B has).
B (possessed) gains Province. The 2 coin tokens are, incorrectly, not deducted from B's total.