That's the effect of caster on camber at the wheel. As the steering is turned, the outside wheels go more negative on camber and the inner wheels go more positive. BMW's seem to have high caster, perhaps 8 or 9 degrees, so it makes for some extreme camber change at high steering angles.
This effect can be used to align the car at home if you have adjustable top plates. Once camber is matched side to side, you turn the car left to right and measure the camber change. Once that is equal on both sides at identical steering angles, you have matched the caster as well side to side. Matching the caster does wonders for steering feel and straight line stability.
Anyway, this is 1.5 degrees negative camber and some lock-