Crankcase pressure/volume build up

[Makmak]

I have competed a blow by test for my ISX871 850K (Correction..it has a second motor mileage supposedly 600k)
As per Rawzes blow by test video. As I increased my rpm slowly to 1500 the difference in the water level kept increasing and oil was coming out of the dipstick. I have checked for the usual blockage related stuff...crankcase filter..blow by drain tube..etc
What can cause continual building of crankcase pressure? I suspect the turbo but how would I test for that? I have not performed a compression test. Engine runs smooth. I performed a cylinder cut out test with Insite and it seemed okay. I'm at a loss!