With no diss meant, that's sounds more like operator error than app error to me.
To me, if you're going to be away from the phone for long enough for the screen drain to be an issue, you shouldn't have the app turned on. You won't be there to see it anyway.

You can also set the app to sleep when you do.
I am fairly observant when my phone IS around, the screen won't have to stay on long I don't think.
And, for the duller knives in the drawer, you can even set an Audio notification that repeats that you have a NoLED alert on your screen. You only have to be within earshot to know you missed a call/text/etc;
Sounds to me that if it's a bad battery drain, you're not using it right.
Bruce in Ocala, FL