I have a one plus 7t the phone works fine, but my Google messenger, started acting up if you open the app for any reason it won't close you can't swipe it away, if you restart it returns with messenger opened, if you go under settings and force stop it the app doesn't close, I found the only way I can remove it from being on my screen is to clear the cache and the storage, then the app will close and disappear from the screen. But the moment I opened the app the problem returns back . Frustrat