Yanmar blowby or normal?

I looked at a Volvo ECR88 excavator with a four cylinder Yanmar 60 horsepower engine today. The engine is early emissions so it has a sealed crankcase vent rather than a drip tube. 3100 hours and maintenance looked good. It was stored outside and started up in 30 degree weather with just a few seconds of preheat. The engine ran well at idle and higher throttle with no exhaust smoke. BUT - when I pulled the dipstick at idle a lot of oil droplets started blowing out, coating my finger in a couple seconds. Oil droplets also blew out when I pulled the oil filler cap. There was no visible smoke from either the dipstick tube or oil filler and the crankcase vent is sealed. There was a light pulsing over the dipstick tube but no pressure if you put your finger over the tube. The dipstick tube and filler do not leak when closed and there is no other visible oil leakage anywhere on the engine. The excavator is at a dealer and the mechanic did not believe the oil droplets were due to worn rings or blowby. They were going to check for clogged crankcase vent and do a compression and leak down test. Any comments on whether this oil slobber is normal for larger Yanmar engines. Any comments on the Volvo ECR series and the ECR88. I am looking for a midi excavator for land clearing. TIA Jim