Smoke alarm notification only appears after unlocking the screen

Dear Home Assistant fans,

I have a quick question I hope someone can help me with.

I’ve recently purchased a Zigbee Frient Smoke/Heat Detector and am currently setting up an automation for it. Everything seems to be working smoothly and promptly, except for one issue:

When my phone screen is locked, the alarm notification doesn’t come through.
As soon as I unlock the screen, the popup message appears immediately.
Does anyone know what might be causing this?

I’ve already consulted ChatGPT and verified all the notification settings on my phone, but unfortunately, the problem persists.

Thanks in advance for any insights or suggestions!

Best regards,
Hans

data:
  title: 🚨 Brandalarm!
  message: Er is rook gedetecteerd in de keuken!
  data:
    channel: Brandalarm
    push:
      sound: alarm.caf
      critical: 1
      ttl: 0
      priority: high
action: notify.mobile_app_gsm

Executed actions:

  • Disabled battery optimization for Home Assistant
  • Locked the Home Assistant app in memory
  • Allow background activity
  • Turn on “Show on Lock screen
  • Enable “High Priority” notifications (CANNOT FIND THIS ONE)