Les, I am thinking your first option above may be the cause. I have not had a chance to drain the lower unit to verify milky oil, but, I did find a loose vent hole screw. I was able to turn it tighter by about 1/8 of a turn. I am thinking water may have gotten in. It would make sense that if water got in the lower unit vent hole, the oil would float to the top, then out the drain hole when tilted up. It seems to drip more oil after the motor is sitting in the up position over night.
Dave