Volume is set to zero after alarm plays

I have a Motorola g6 mobile phone, Android 12, and Sleep as Android, paid version.

App is set to use the motion sensor and lullabies.

On waking up, the sequence is:

  1. Alarm sounds. I press snooze.
  2. Some notification arrives, and it sounds (so DND was disabled already).
  3. Alarm sounds, second time. I press dismiss.
  4. I try to close the app
  5. I unlock the phone
  6. I press the volume up key, and I see that it is set to zero. I think it is the multimedia volume.

This happens everyday. I noticed the problem when the phone own alarm, which is set to an hour later, for backup, would not sound. Or if I tried to play a youtube.

Ideas? Some configuration? Is it a bug?