So some oil is coming out while they're sitting? If so often times pressure builds in the tank from temperature changes and oil will be forced out. Pretty much every saw I've ever owned leaked some oil after sitting awhile if I didn't drain the tank. I consider it normal as long as the oiler functions properly and oils the chain.
A little leak is normal. Take the bar off and there is a little valve that equalizes the pressure in the tank. Use something small to push on the valve a few times. It may have a piece of dirt in it. If it is not that, it could be the oil cap or oil line.
Ambient temperature will also affect bar oil leakage. I keep some of my work saws in my truck tolbox. When it gets hot (and in the sun that box can get REALLY hot) it pressurizes the oil tanks on the saws and I'm pretty sure that's what bleeds the oil out..... Best advice I can give is to drain the oil out of the saws when storing or not using. That will eliminate leakage.
