According to the rules, a piece cannot move back to the square it moved from on the previous move. As I understand it, there was a bug that allowed such moves in certain circumstances. Has that bug been fixed?
(hide) If you are waiting for your turn, click on "change" next to the "refresh" on the main page, then set refresh the page to 30 seconds to get your turn to move displayed faster. (Servant) (show all tips)