Edge glow (halo-like) around iphone 12 pro screen

Hello, so there's a glow around the edge of my iphone 12 pro when I woke up today. It already happened 3x already. The last time it appeared was around 3 weeks ago. The same scenario happens. I woke up, then I find the edge of the screen of my iphone glowing.

After 30 mins of using, it fades until it completely goes back to normal. I'm not sure if its a software bug or hardware issue, but i haven't experience anything unusual after that.

The one thing in common for three instances was that the first two scenario, I left my phone fully charged in the evening, and find the edge glowing when I woke up in the morning. I charged my phone with low power mode on and on airplane mode. last night, I slept at 40% battery with low power mode on, I woke up in the morning finding the edge glowing again.

I'm not sure if temperature is a factor but the phone wasn't hot when I slept. The case isn't that tight also.

I never put my phone in my pocket nor drop it from a high point so Im pretty sure I didn't damaged the screen nor the phone.

Here's the photo of my phone last morning: