Not sure if this is an active bug or not. However, I've noticed recently when I add in cards for my wish list by editing the column on the main screen that it shows a warning icon where the set symbol normally is. If you clid edit card details you get the following error shown;

"To indicate which of the 3 cards you are trading, check the boxes in the last column. "

Unfortunately in the case of this error there are no cards in the list for trade. Just cards in inventory and additional cards desired in the wish list column.