Your beam with Xenon headlamps is controlled via a couple of factors:-
Self leveling system is operational
Load being carried
Self leveling is mandatory on Xenon ( HID ) and operates via sensors on suspension. Those sensors detect vehicle weight ratio at front/rear and adjust headlamps to prevent glare to oncoming vehicles.
Therefore, if you have weight in rear of car which raises front, system will compensate by lowering headlamp beam. Do you have anything weighty in rear of car?
Failing this, if you bought from Lexus dealer, it would have a 1 year warranty so take it back & ask them to check Auto leveling system.
Just as a final check though, take off auto and turn on manually to see if this makes any difference.