I’m using a Lenovo Tab M10 Plus 3rd Gen with Android 13. All of a sudden, I get Systm in a phone size mode. There are 3 dots at the top where I can select full screen, but nothing happens. Any idea what’s going on?
I have the same device and it’s working fine for me. Only suggestion I can give is to maybe try the old delete and reinstall trick, that has a habit of fixing strange behaviour. Or just try restarting it, the app and/or device. 
OMG, so embarrassing. I did a force stop and it fixed the issue. I can’t believe it. Thanks for your wisdom. 