Note 9 animations dropped frames when closing certain apps

[Rukbat]

You're in an app, then hit the home key

That's using the phone (any Android phone) incorrectly. "Ending" an app by using the Home key leaves the app running, using battery, slowing the phone. The Back key is for closing apps. The Home key is for running the browser when you're in an app and need another app for a moment. Then you kill that one and go back to the one that's still running (until you're done, at which time you use the Back key to kill it).

Maybe that's why so many people are getting shorter battery life than they expected.