Difference in screen brightness on the left side of the notch

It's been 5 months since i used my iPhone and actually from the beginning I already realized that there was a difference in brightness on the screen on the left side of the notch when I dimmed the screen. The screen will look normal with the normal brightness or the brightest but if I dim the screen it will look like a difference in brightness or a brighter line on the screen. is that normal?