Cummins isx cm570 leak between compressor and power steering pump

After reading alot of post, notice when these compressors leak oil is usually into air tanks..

My issue is engine oil leak between compressor and power steering pump.. I bled power steering and put the clear dealer stuff. So the resvoir oil is not engine oil and also can tell by the smell of the oil.. also has knocking sound that goes away when the "excess" air dumps once air is built up.. or turning the steering wheel will change tone of the sound.. btw the power steering pump is new ..

Why is there a gasket in between , is there suppose to be oil between pump and compressor for the shaft or smtg??...
Builds up air good just don't know if oil is suppose to come out even if there was no power steering pump behind compressor. "Mechanics" around here (where I live) can't give me an answer even after replacing the gasket again between compressor and pump if it's the compressor from inside or.smtg. thanks in advance for any input .