I sold my 2011 535xiGT a year ago just because of the low voltage problem at 9K miles. Could not keep the battery charged even here in Southern CA and the dealer postulated that the vehicle needed to be driven an "average" of 37 miles per day to keep the battery charged. Heck, I even got warnings after a 400 mile trip! I'd get all sorts of warnings from "car will not start if stopped" to "overheating" to "Differential failure" to many more. Dealer kept car several times for two days and no fix. Car was totally unreliable and BMW never could figure it out. Funny thing is that I got a call a week after I sold it to a Ford dealer and the local BMW dealer had towed it in and wanted to know what I wanted them to do with it! LOL. I really, really wanted to tell them!
As a sad aside, my wife's 2010 GT with just 7K miles had some intermittent left turn signal issues that seemed to self-resolve. She went in today for an oil change and someone must have disconnected the battery, Radio stations all gone, left signal no longer works, warnings on vertical headlight adjusters out, adaptive headlights out, and more. All from a trip to the dealer. Thay have the car back and will likely have it for an extended time as they have no idea what's wrong. their wonder diagnostic machine can't find a fault and even if it can, they're certain they won't have parts.
Good old German uber engineering at work.