Well, crap.
This is a known common problem with OEM intake systems.
Commonly, the PCV system is vented to the intakes. This results in oil vapor in the intake system. What you see is the results.
This is the reason for "catch can" systems in many cars. Looks like ours needs one too. DAMMIT.
I found one for the F10. Sigh.
https://burgertuning.com/products/bm...u-bmw-m-engine
Shawn