How do I fix the brightness glitch on my iPhone 13 Pro

There are a couple of reasons why your iPhone 13 Pro's brightness might be dimming even though the control center shows full brightness:

• Auto-brightness: This is the most likely culprit. Even if you haven't adjusted the brightness slider in the control center, auto-brightness might be enabled, and adjusting the screen's light level based on the ambient light sensor. You can check this by going to Settings -> Accessibility -> Display & Text Size and turning off "Auto-Brightness."
• True Tone: This feature automatically adjusts the color temperature of your display to match the ambient light. While not directly affecting brightness, a shift to warmer tones in low-light environments might feel like dimming. Try turning off True Tone in Settings -> Display & Brightness and see if the issue persists.
• Low Power Mode: When enabled, Low Power Mode reduces background activity to conserve battery, which can sometimes include dimming the screen. Check if Low Power Mode is on (Settings -> Battery) and disable it to see if the brightness issue stops.