Something similar happened to me last weekend. I'd been riding high-80's into a strong headwind for about half an hour when the bike started to sputter, like it was running out of gas. Had a full tank though. Dropped speed to low 70's and the bike recovered.
My conjecture is, I'd drained the carb float bowls by the long high-speed run. They weren't filling fast enough, so the bike was starved for gas. Could something similar have happened to you? Highway in 4th gear is reving it, perhaps the float emptied just as you pulled in the clutch. No gas for an instant, clutch out, engine died.
If that was the case, then by the time you got to the shoulder, the float bowl would have refilled, so your engine started normally.
It's a theory, anyway.
The journey is the destination.
2006 VN750 (SOLD)
Red spark plug wires
Stainless Steel brake lines
Stiffer fork springs
Givi bags, Wingrack mount