What happens when you play one of these cards, and there are only two cards remaining in the relevant deck?
A) Nothing happens, because "Reveal three cards" can't resolve. No cards are revealed or moved.
B) The card does as much as it can. Two cards are revealed. The player puts one on the top of the deck, as ordered, then puts one on the bottom. There is no third card to also put on the bottom, but that's OK.
C) Something else...
It's a rare edge case for this to be possible, and even rarer for it to *matter* what order those last two cards are in -- but I wanna know!