If projected on a wall, The beam pattern is supposed to look like this:
Some wrongly conclude that their lights are poorly adjusted and point their left headlamp higher. As Grip says, that dark area is supposed to keep oncoming traffic from being blinded. I haven't checked on the MO, but on my S if I cover one headlight the pattern from the other one STILL looks like what I drew above.... even more evidence that it is intentional.