https://www.reddit.com/r/AskMechanics/comments/14wnva4/what_causes_stuff_like_this/I guess report(s) on that thread sound similar enough to show this isn't completely unprecedented.
In looking at the hole in the wheel, it's hard for me to tell which way it is deformed. If I had to guess it looks a bit deformed towards the inside of the wheel, meaning something came in through the tire and then into wheel. The holes in wheel well and bed, metal deformation at the edge of the holes show something came from inside the wheel well out through the bed - shot from tire up through the bed.
The photo in the reddit thread looks more clear as far as the puncture in the wheel itself, it's bowed out towards the middle of the wheel which would indicate more clearly to me that something can from the tire side. The wheel photo in the OP's post shows a cleaner break of metal but upon reinspection the surrounding metal does appear to be a bit bubbled towards middle of wheel which again would indicate something came through tire and then through the wheel.
Regarding meggy09's theory -
ran over something that punctured the tire then the wheel, made it about 135 degrees around the wheels rotation and was flung through the wheel well - my initial thought was wouldn't there be TWO holes in the tire then? Something passes through outer tire, busts through but lodges in metal of wheel, then flung back out due to centrifugal force puncturing tire AGAIN then wheel well and bed.
But no, not NECESSARILY a second hole of the object was longer.
I could picture a thin piece of metal, at least 12" long, lying parallel to the road lines. Meaning the truck's front left wheel drives over the entire length of the piece of metal. When front left wheel reaches end of the piece of metal it pops up just the back end of the metal - like / but less of an agle - then back wheel hits it in a magical way that leads to it penetrating the tire and wheel. It's long enough to be in both holes at once (HEY now) and then get's ejected through bed after a quarter or half rotation. Only one tire hole because it's a longer piece of metal.
I can at least picture that, don't know what other scenarios would explain it given the wheel puncture location and size (which is bigger than other holes btw, based on aluminum fracturing characteristics potentially) and angle of departure of the object.
It is scare to think of the velocity of that object and, IF truly flung by the rotating tire, what would have happened if it was angled toward the cab of the truck.