XDJ RX2: Deck slowly slipping off sync

I just bought this controller from a friend and i swear the first night it worked fine but now it seems like one of the decks is slipping off sync! Wether its in Sync or im beatmatching it just super slowly slips off the beats being synced. Its like one of the jog wheels is being super slowly jogged. You dont notice for like one phrase but than it just slowly gets unmatched. 

Has anyone ever come across this issue? This is my first time owning a rekordbox controller so Im really hoping im doing something wrong and its not broken. Please let me know asap.