New Redmi Note 9S - notification sounds don't play properly


Dec 10, 2020
RN9S, 12.0.2 stable.

Particularly with headphones and while playing music via Spotify. Notification sounds should play over the top of the music, but they don't. I have checked all permissions and notification priorities, both in-app and on system level.

The phone vibrates for notifications, but no sound.

Sometimes, when headphones are unplugged, I actually get TWO notification sounds from LINE when I receive a message.

Hoping a dirty flash will fix this, but does anybody have any suggestions?