Might be the PCV syatem dumping oil into the Turbo and pushing it out-- common to have oil in the boost system. You can reroute the system and the engine will stay cleaner!
Also another possibilty is a leaking valve cover gasket, or a turbo drain tube. You need to inspect it closer.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.--- Jerry