Yeah, this one's common. It's usually not a catastrophic failure, just how the oiler system works when the saw is stored wrong.
The bar oil tank is vented. If you store the saw flat on its side, or with the bar nose lower than the tank, oil can siphon out through the oiling hole in the bar. First fix: always store the saw with the bar pointing up, or lay it on its side with the bar and oil tank facing up.
If it's still leaking while stored correctly, check the oil cap seal. Make sure the cap is on tight and the rubber gasket isn't cracked or missing.
If that didn't work, the oil pump itself might be faulty, but that's less likely. A more probable cause is a clog in the oil passage from the tank to the bar. You can try cleaning the oil outlet hole on the saw body and the matching hole on the bar with a thin wire.
Heads up: Use the right bar oil, not motor oil. Thinner oils leak more easily. And that pool of oil on the floor? It's a fire hazard and a slipping hazard. Clean it up.