Treble control not working infinity!

I have a 2018 Hyundai Sonata Limited 2.0T, which I purchased about 2 months ago. Very happy with it, but I noticed that the TREBLE control doesn't work when listening to the radio/mp3 player! The slider goes from -10 to +10, but there is no change in the sound! The BASS and MIDRANGE controls work fine, even though I would have preferred to have the MIDRANGE frequency higher (about 3kHz). Does anyone else who has this vehicle notice the same problem? I'm curious if it is just my radio... well it isn't... read on.

*** UPDATE***

IT DOES IT IN ALL THE 2018 Sonata Limited 2.0Ts! HYUNDAI/INFINITY FIX THIS ISSUE!

Setup/Sound/Tone/Treble slider

Thank you for any reply,

John