I want to check into this fully for you and there are some things I need to know first. What is the channel you're going to and what is the screen setting you're changing it to? When you are on the channel that has the different sized screen, are you going to a specific channel to get the issue or any channel?
I have tested it on different channels as well and it will default back to Normal before changing the channel. I am reaching out to our engineer department to see if this is normal or if there is an issue that needs to be reported.