Like I said 'it was a RUMOUR unsubstantiated'. However taking some guesses at the RUMOUR one may GUESS that perhaps the helo nav equipment became faulty; or the ship did not have good beacon equipment. Once a HELO is in the water I'll imagine a rescue beacon would make locating the HELO / survivors easier. Aircrew with helo experience could imagine better scenarios, I'm just an old fixed wing chap from wayback.