I've seen scooters puke a lot of oil out of the vent tubes when they've been setting for a while, usually a couple of weeks or longer. Since the cases are lower than the oil tank the oil gravity feeds past the check ball and into the lower end. When you crank the engine the scavenger side of the oil pump can't pump all of the oil back into the tank quick enough and the oil takes the path of least resistance-out the breather. This is a one time deal until the bike sets again. This wouldn't have anything to do with the oil light staying on though. Check the pressure with a gauge. If there's oil in the tank and the gauge stays on zero, the first thing to check is the oil pump. If it picked up trash and locked up, it can strip the key in the drive gear on the pressure side of the pump.
You could also check the pump by pulling the return line off of the oil tank. Crank the engine an if everything's working it'll pump oil out of the line. No oil coming out of the line--check the pump.
Larry T
You could also check the pump by pulling the return line off of the oil tank. Crank the engine an if everything's working it'll pump oil out of the line. No oil coming out of the line--check the pump.
Larry T