Running out of fuel is pretty common in military vehicles as the fuel gauges are at best reliable to half a tank.

Drivers are supposed to track how far they have driven, but if its driven by multiple people and someone forgets to log distance or the vehicle is forced to idle for a long time the distance can be off.

Also a broken fuel gauge will not mark the vehicle as a casualty. Its not critical equipment as your supposed to be tracking fuel usage as a driver.