If you have xenons with auto leveling the rear right sensor works for both headlight leveling and rear suspension. If the sensor was some after market unit it's not uncommon that it's not working as intended when there should be separate circuits for both systems.

__________________
E39 530dA -02 M-Sport Messing metallic
E53 X5 3.0dA -06 Sport Stratus grey
E70 X5 40d -12 M-Sport Space grey