The Premiership champions were informed by Athletic Bilbao over the weekend that the only way they’d be able to snap up the Basque midfielder would be by paying his buyout clause in full.
Three men claiming to be acting on behalf of Manchester United soon turned up at La Liga's offices in Madrid to pay the €36 million sum.
"They left an hour later saying ‘we've had a few bureaucratic problems, we’re going to have to come back'," Guardian journalist Sid Lowe told ESPN Sports.
"We waited and waited and eventually received a (British) Press Association report saying 'these three men have nothing to do with Manchester United'. It is absolutely bizarre!"
Manchester United agents involved in the negotiations have talked down this version of events.
Regardless of what really took place at La Liga's Madrid offices, Manchester United manager David Moyes said the deal had fallen through because the asking price was too high.
"I really like the player but we thought the buy-out was the wrong valuation," he said.