Bingo ! Thank you agsteele...it worked. I went in and found the Batter Optimization settings. Settings - Apps - Evernote - Battery and the app was checked off as being optimized. I chose unrestricted instead and backed out to the home screen. I've run a series of test tasks, with Evernote either not running or not running and the phone asleep. In every case (so far) the tasks are now notifying. I was actually able to change the Evernote notification sound to something different, to prioritize even more, the task triggers. Very much appreciated !