Hi everybody.
When i lower driver's side or front passenger's side power window,i can hear noise like single knock from the door,approximately on the 1/4 from top of window lowering path (1 second from starting auto lowering).
When i raise window then there is no single knock noise.
Speed if lowering or raising is normal.
​​​​​​This happens on both sides and on same window height,knock sound is the same too on both sides.
Is it normal?

 

I've never heard any noise when raising or lowering my windows. It seems really odd that it would happen on both windows! What year is your NX?

 

2015. Seems strange,because speed of raising or lowering is normal,work as usual. No window vibrations,freezes or something like that. Just this sound.
When start lowering,window speed is slow for a second,then this single knock noise,can hear it near door,then normal speed. At the end of lowering window slows down and dissapears inside the door.
When start raising, speed is slow for a second,then normal.at the end of raising window slows down without any knocks or noises. Window closed.
Passenger window behavior is the same.
Slow speed at the start and at the end is by design,i think. Some premium cars have this feature.
Rear passengers windows don't have this sound.

Don't remember,was this sound from the beginning or not.
Rarely open my windows.
​​​​​​So can you hear that sound? You need to turn off radio and climate.

 

I can hear something similar, happens only at certain position on a way down, can hear it on all four, might be related to cold temperature, today is below 40F.

 

Exactly, i heard it when it was cold earlier this week, but today is rainy and warmer, and no noise.
Ok, assume this is not bug, but feature

 

This is starting to bother me, it feels sometimes that windows are about to stuck in the middle on the way down, also makes unpleasant noises. My other very old car doesn't make them, why new Lexus would? I am going to bring car for service.