Thank you for your support of Xiaomi products. The phone will undergo strict professional inspection before leaving the factory, so you can use it with confidence. The Xiaomi 15 Ultra uses LTPO (Low-Temperature Polycrystalline Oxide) technology, which allows the screen to dynamically adjust its refresh rate. When the screen display content is not updated, the screen refresh rate will be reduced to reduce power consumption. During the refresh rate change, you will notice a slight brightness change. These changes are designed to optimize power consumption without compromising user experience, but they will cause subtle shifts in brightness and color when transitioning between frame rates. This is a normal phenomenon designed to balance power efficiency and visual quality. The slight color and brightness changes during this transition are expected and should not affect the overall usability of the device. Please feel free to use it.