Sheffield seem to be stating that, whilst he was subject to disciplinary measures, he hasn't actually been sacked. If he had, they wouldn't have a leg to stand on and wouldn't have made this statement.
Bulls' best best is to pin this on the player and/or his agent, saying that they were informed by the agent that he was free to sign. Now that they're aware he isn't, that they will of course not be signing him until he becomes free. Alternatively agree a transfer fee, but I can't see that option happening.
To me is screams of the player or his agent being the one in the wrong. Even Bulls surely wouldn't be stupid enough to know he was still under contract at Sheffield and sign him anyway (I appreciate they have shown examples of similar stupidity in the past). Whether it's down to Sheffield telling the player he was released and it not being the case, or whether it's the player/agent jumping the gun, will remain unclear. Either way, the worst Bradford will have done is not ask for proof that he had been released, and taken it on the word of the player/agent.