I know this bug has been reported before, but I've never seen a description on any way to recreate it. Well here's one,
Scenario using Klondike3 game:
The last card in the deck is a 4 of hearts.
There is an open 5 of clubs in the tableau but you don't "see" it.
You 3-finger tap (or 1-finger quad tap) to go to next card.
You are told that there are no more cards in deck.
You remember that 5 of clubs, move to it and 1-finger triple tap to move the 4 of hearts on it.
you are told you can't place a 4 of hearts on top of a 5 of clubs.
However, if you 3-finger swipe to the left to undo one move, it will now let you put the 4 on the 5.
Hope this helps,