I'm the new owner of a 2009 E92 and have my first mechanical problem. My sister pulled up the convenient entry lever on the passenger seat to get into the back, and the backrest stuck in the forward position. After reading the pertinent section in the manual, I pushed back harder on the backrest, and it released and flopped all the way back and locked. Pulling the lever up released it so it would swing back forward, but would not stay in the normal upright position. It wants to flop either all the way forward or backward and lock. I've studied the manual carefully and tried all obvious maneuvers. None works, including the electrical adjustment. Did we break something, or am I missing something?