banding artifacts issue on highlight/specular on Quest2

Hi folks, I have a weird issue with highlights.
when our app is running on Quest 2, the highlight of a simple directional light is banded/pixelated, as in image below, it goes onto different materials.


but in the editor on PC it is fine


i have only 1 directional light in the scene, with 1 skylight and 1 sky atmoshpere

Has anyone encountered similar issue before?
any clue would be more than helpful.

thank you!!