Ok just curious since there's a check valve in the oil cap, I pushed oil in a cold to hot situation before.Shed. Curious where this is going... If you bring it in to a warm building after working out in the cold, the temperature increase pressurizes the tank and forces the oil out?
FWIW Grumpy (also a 10-10 | 600013U) sits out there with Bits and does not exhibit this.
There is a tiny ball bearing pressed into the oil tank right above the bar mount plate , most of mine still have sealant from the factory around them , it could need a wack with a jeweler's hammer or it could have fallen out. It loks to be a passage block.