Some underlying databases changed while moving from A9 to A10. Is this custom notification sound feature present in new A10? If yes, could you disable all your old settings and enable them again?
Yes - known issue for the Beta. Should go away when we get the build certified.
Good to get feedback on that. We can decide between the two once more users chime in .
Opening a bug for this. As a workaround till we fix this, you can pause the music on the phone before powering off the speaker/headphones.