This would be easier to identify if you get some logs pulled. I'm going with the majority in saying its a leak in the system and if it is, logs will show AFR's out of the norm.
E92 '08 335Xi 6AT - Cobb AP V2, ar design DP's, Race Cats in the mids, Corsa Axleback, VRSF CP w/Tial BOV, VRSF 7" FMIC, BMS DCI, BMS Cowl, H&R Coilovers, Renn Motorsport RS-51's, Alpina TCU Flash, Turner Boost Gauge, Fully Coded.
Awaiting Install: Evolution Motorwerks Oil Cooler, RB PCV+Cap, Aquamist HS4, VTT Inlets.
Best 1/4mi: 13.201 @ 106.93 / 2.0 60' / DA=9300ft Bandimere Speedway