Steering wheel fault
From your description I dont think I had exactly the same fault as, after stopping my car, the computer would not allow me to restart the engine hence I was towed to the garage. I think mine might also have been a computer fault but the BMW franchise licked their lips and hit me for 700 Euros. They changed a simple microswitch on the steering column (80 Euros) and then did diagnostics and reprogrammed the car computer. Total rip off, BMW know all about yet refused to help.
With it being a steering fault I would get it seen to, but complain bitterly to your dealer and to the BMW (lack of) help line, you just may get some discount.