Hi all, guess there is no "one cause" for this.
It just happened to me and I almost sh-t in my pants.
It happened while driving on a highway at 80 km/h! I had started the drive after 1 week of not using the car, 15 minutes after starting the car, and strangely, the oil temperature was still in the "very cold" area.
I didnīt do anything, and once the oil temp went to normal (I think between 70 and 120°C), it dissapeared...
Since the official BMW service here in Argentina is crap, my idea was not to take it unless I saw this a second time.