Playing on my android phone, I encounter a bug where it showed my opponent with more cards in hand than they had.

My opponent was showing 3 cards in hand: one disdainful stroke, one Riddler (both of which I knew about from a previous The End), and one unknown card. They then proceeded to warp Riddler and draw 2 cards even though the animation showed them holding stroke and another unknown card as the Riddler trigger resolved.

I cast Binding Negotiations the next turn and it shows me their hand of stroke, Forest, cub.. and a face down card in their hand.