Too much crank pressure, Check the PCV valve and run the PCV system the way it was from factory, from valve cover to intake manifold and from valve cover to inlet pipe before the turbo.
Pull the oil cap off with the engine running and rev it a couple times, if exhaust comes out of the valve cover you probably have some seized piston rings, try a Seafoam oil additive cleaner and a seafoam intake manifold and piston cleaner.
If/Once the PCV system is working properly and there is no exhaust blowby and the dipstick keeps lifting, bend the dipstick at the cap (that sits over the dipstick pipe) so that the rubber at the top of the dipstick is closer to one spot on the cap, this will pin the dipstick and cap on either side of the pipe and keep the dipstick in place.
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