This bug will appear if battle.net is displaying the new wow AH mount ad when the system (monitors) is supposed to go idle.
Microsoft Windows [Version 10.0.22631.4317]
(c) Microsoft Corporation. All rights reserved.
C:\Windows\System32>powercfg -requests
DISPLAY:
[PROCESS] \Device\HarddiskVolume3\Program Files (x86)\Battle.net\Battle.net.exe
Video Wake Lock
SYSTEM:
None.
AWAYMODE:
None.
EXECUTION:
None.
PERFBOOST:
None.
ACTIVELOCKSCREEN:
None.
Similarly, I often find that having the BDA app open for a some length of time permanently prevents my monitor from entering screen saver.
The only way I can fix it is to turn off the sceeen saver, and turn it back on. But, after the BDA is open for a while again, the screen saver breaks again.
This is happening to me as well. I haven’t identified any specific activity in the battle.net app that causes it, but having the application running does often prevent the monitor from sleeping, with the same request present in the powercfg list.
Having the Battle.net app running idle in the background shouldn’t be constantly keeping the monitor awake 
.
This is still happening.
It should be fixed ASAP. You’re wasting people’s electricity by leaving their monitors on for hours at times when they should have turned off after only minutes. This could be affecting hundreds of thousands of people with the bnet launcher installed and they just haven’t figured out what is causing it. I assumed it was my web browser at first but couldn’t fix it for a week or more before finally discovering it was the bnet launcher. It wasn’t happening all of the time and I couldn’t figure out what the common factor was until I discovered it was bnet and only when on a game tab in the launcher that was showing a video or ad of some kind.
It’s 100% being caused by your program as confirmed by powercfg -requests
I have to either close the launcher or swap to a game tab that isn’t playing some kind of video in order for my monitor to not stay on permanently even after I lock the screen.