Thank you for your support. Each phone undergoes strict professional inspections before leaving the factory, so you can use it with confidence. Several factors will make the phone have color and brightness when switching the refresh rate, such as display calibration, dynamic adjustment, graphic processing and software buds.
The Xiaomi 14T experiences slight color and brightness changes when switching from 120Hz to 60Hz after entering the browser or reading while in dark mode for 3 seconds without locking the screen. OLED screens will display slight color differences between 120Hz and 60Hz in low-light conditions, which is normal and will not affect your usage. You can try turning off the dark mode or setting the refresh rate to 60Hz for a better experience.