Anyone know why AS 712 was diverted all the way back to Seatac from Billings, MT area (original route was SEA-STL) this afternoon? Live ATC (ZLC sector 15 from 2130 2200) doesn’t give any clues other than “the company hashing it out” over whether to turn around. My elderly parents were on the flight and they were told it wasn’t a mechanical issue. No apparent medical emergency or unruly passengers, either. Got to STL eventually 6hrs late after changing planes. At least they each got $400 for their trouble….TIA.