It's an accessibility feature called "Time To Take Action" which prolongs the amount of time an app or system message remains on the screen. you can change this easily in settings by using the search function within settings or go into Accessibility>advance settings to find it and modify the timeout length or disable it.
UP because i am experiencing this. This is just annoying! Can we atleast swipe it off.??? Plus it stays for more than 5 seconds!!! How many updates , yet this is still unsolved! Im using note 10+