If you set "Pixel Light Count" in the graphics settings of VRChat and then set "Quality Preset" later,

"Pixel Light Count" will not change in appearance,

but the value will actually be overwritten.

For example, if you set the quality to "Low", it will be "Off" even if it looks "High".

Preset "High" → Pixel Light Count "High"

Preset "Medium" → Pixel Light Count "Medium"

Preset "Low" → Pixel Light Count "Off"