Measure ride height from center of wheel star to the underside of the fender lip. What is this measurement? Is it the same side to side? If it is, you probably have something broken, bent, loose, or worn. When lowering the vehicle you are changing the suspension geometry and possibly changing the way the self levelling system adjusts the level. IF the system, for example, is using extra capacity to level the right side, it may not be working correctly on the left side. I do not know for certain, but mentioned it as a possible/probable cause.