Super Zoom

Several times a week my iPhone X (iOS 15.1) goes into what I can only describe as super zoom. The screen is so zoomed in that I can't zoom out. If I press volume & side buttons to shut down, everything is so zoomed in that I can't navigate to the power off button to shut down. I have been using the method of (1) pressing one volume key; then (2) pressing the other volume key; then (3) pressing & holding the side key until the phone shuts off. This is a pain and it sometimes takes several tries to get this to work, but eventually it does. Any ideas on how I am getting into the super zoom mode? Or is this a bug?