Yup my 2014 E450 2 valve V10 sucked a valve at 104k miles. Just got the bill for the new engine & labor $13,500.00 (Connecticut)
I bought the van new, oil changed every 6k full synthetic. Never pushed van, it's not a camper and we are "flat landers" (no decent mountains to climb). Van used locally as service van by me the owner. Engine mechanic really has no explanation why it sucked a valve except that he has seen this happen with over revved engines. I saw the valve broken clean off at base of stem. Valve face then chipped off a piece and got sucked back up through the head into the intake plenum. I found both valve stem clips undamaged. The night before I parked the van in my driveway after using it all day. The next morning I auto started the van as I have done every morning since 2014. It started and after I went outside I could hear a chugging out of the exhaust (no smoke of any kind). I thought oh great another blown out plug but knew it was way to quiet for that. I shut it down thinking maybe a fouled plug and restarted it to hear the valve or something jamming around the engine. I shut it down again and it just jammed because of the valve in the cylinder. Mechanic says he has heard that after market auto starts have caused this sometimes because the aftermarket stuff kinda goes bypasses the computer for a moment to start the van and the fuel injection system gets screwed up and basically over revs the motor. I did not hear this motor over Rev but I could have missed it all together as I was still in my house. I asked about the Rev limiter protecting it and he said that somehow I must have floated the #1 valve causing the clips to fall out and drop the valve. He states the after market auto start could temporarily lose computer settings and bypass or not have the Rev limiters protection. I'm very happy with the mechanic and he is only stating a possibility of why this happened from what he has heard happen to other unexplained engine failures . He is not staking his carreer on this nor is claiming this to be my cause. He's offering up an possible explanation as we can't see any other cause or reason for failure. If your still reading this at this point ....my question is what's your opinion on why this engine may have failed at such a young age ...at an idle in my driveway. All opinions welcome except the usual "it's a Ford" remarks. I own it already and know what brand it is. Thanks everyone.

 

The suggestion of the engine swallowing a valve and locking up is not unusual for revving up a cold engine. They will send a rod through the side of the block too.
Unfortunate, but since you were not present to see exactly what happened, we can only go by past experience.