On February 10 it issued a statement claiming that it had a problem with “transaction malleability” - in essence, somebody could withdraw cash and then alter the ID of the transaction to make it appear that it had never occurred, then request it again. It called this a “bug in the Bitcoin software” but Bitcoin’s developer community pointed out that the issue had been known about for some time already, and that it was less a bug and more something which needed to be taken into account by developers when creating an exchange service. Other exchanges popped up to say that they were unaffected.