iPhone 13 Pro Max Sudden Screen Dimming Overlay

Ever had your iPhone 13 Pro Max randomly and suddenly dim the screen brightness? It’s not related to the auto-dimming. What happens comes on suddenly and with no warning and does not happen when the phone is noticeably hot and does not seem to be affected by changes in ambient light. Basically for seemingly no reason the whole phone display brightness will dip by what seems to be 30-40% in a split second. No warning shows, you check the brightness and can move it all the way up, but it’s literally no longer at full brightness. It’s like there’s a transparent black overlay on the screen. Then a few minutes later it randomly instantly goes to full brightness again. I feel like this is another random iOS bug that has gone unsolved for years because everyone assumes it’s the auto-dimming, but the auto-dimming happens slowly. This does not as it happens instantly.