This thread started more than a year ago, but hasn't been active since March this year and I'm faced with exactly the same problem:
Been using Aquamail pro for several years now and am VERY happy!
Initially used an S4 and for the past 1.5 years, Note Edge (which I still see no reason to replace!!!), SM-N915A variant, running 6.0.1 .
Sometime in the past week or so, LED & notification icon stopped appearing. I can find out of new messages/s only by looking the app's icon ans its counter.
I've followed "Paris Geek"'s procedures above, but no change.
Also, I can't find the "Turn screen on" to disable...
Help?