Apple Watch 4 malfunctions when taken off charger

When I take my (brand new!) Apple Watch 4 off charging, it loses its mind for about 5 minutes, randomly going from app to app and showing only corners of the display screen (like Mickey Mouse's ear but not the whole screen that should show up). Pushing the crown can get it to change screens momentarily but it will then start randomly going from app to app by itself again. Has anyone experienced this? How fix? Thanks.