That same thing happened to me when topping off my pickup with gasoline last week. My guess is when the nozzle is held manually just slightly open causing a very low fuel flow, then the nozzle's auto shut-off function is disabled.
BTW, we got to Fallon, NV today... filled the coach at Pacific Pride in Winnemucca, NV on the way through. The fuel prices, while usually lower than in my home area (Hermiston, OR) are way higher here in Nevada. We usually stop overnight and fill at Amargosa Valley, NV where the prices are usually the cheapest around. My brother-in-law, now in Pahrump, NV, said Amargosa Valley's two stations' prices are $3.45 per gallon. He said Pahrump's prices are closer to $3.00 per gallon. The diesel price at the RV park where we're parked in Fallon is $3.29 per gallon.