Just got my S9+ and it seems to have a lot of problems around the Lock Screen (including not waking up for new notifications).
Another thing that's a real problem is that I can't control the volume while on Lock Screen. Wheter the screen is off or whether I wake up the screen, pressing the volume keys up or down has no effect.
How can we fix this bug?
So I actually thought about installing NOVA, but I thought I was going to give Samsung UX a chance first lol. So honestly it's "Samsung stock" at this point. Same for audio, I don't have anything special installed.
It's almost as if the volume up and down were disabled when on lock screen. Even the Bixby button that I just remapped triggers a little notification telling me that "Bixby voice is not yet set up".
Interestingly I just realized last night that the volume key works when on lock screen when connected to a bluetooth speaker.
However, it still doesn't do anything in all other circumstances. Does anyone else have any idea how to fix this bug?
Try this: Go to Settings > Sounds and Vibrations > Use Volume keys for media. Turn ON this option.
I have no idea why Samsung made the default to turn off this option.
I used the app Sideactions from the play store to change the button behavior in the lock screen.