Black Colouring Turns Grey on iPhone 13 Pro Max.

My iPhone 13 Pro Max is 2 weeks old however i’m unsure whether this is a issue with my phone or on going issue with an iOS. I was wondering if anyone else gets this issue.

I use apps like snapchat and facebook and usually the background is of a black dark colour, but yet every now and again for some reason the black colouring in my phone turns to a greyish and lighter colour.

If i reset my phone then the colouring goes back to a black colour.

I have also tried to take a before and after screenshot of the colouring of the black/grey before resetting my phone, and before i reset it the 2 photos both look grey, but yet when i reset the iphone the 2 photos both are of a black colour and back to normal.

Its very strange, also my colour thing in display accommodations is turned off.

Any tips?

Also other colouring on the phone seems fine, but it’s just the black colouring on the phone will just all of a sudden change greyish every now and again and will need a force reboot for it to come back to the normal black colour.

Thanks.