rarely this happens to us in wekan:

when we move a card from board A to board B:
1- card doenst move to board B in clint view but exist in backend ( found it in JSON )
2- card doesnt move from board A and still exist in clint view but when you click on it, board B opens!
3-in board A card just exist in clint view and doesnt exist in backend ( not found in JSON ). the link is like this: mysite.com/boardBurl/cardID
4- as i said card exist in board B JSON, but its listId and swimlaneId of card is blong to board A