zeropc said:

send the wrong copy... yeah right.

Actually, it's way more likely than you think. It's Studiocanal (the film's UK distributor), not Sony, who would have done the deal with Channel 4 and supplied the HD master. If, as I suspect, Studiocanal had an HD master of the unrated cut lying around that was previously intended as bonus material (before Ghost House and/or Fede Alvarez decided otherwise), there would have been nothing to stop someone in Studiocanal's tape library literally pulling the wrong master off the shelf by accident.