Live Activity pushes are meant to be completely silent background updates, so Firebase’s requirement for an alert field is technically incorrect and creates unnecessary sound/vibration issues.

When sending APNs messages with "apns-push-type": "liveactivity" via Firebase Cloud Messaging (FCM), the service currently requires an "aps.alert" field to be present in the payload.

However, Live Activity updates are designed by Apple to be silent background updates, they should not display alerts, play sounds, or trigger any user-visible notification behavior.

Because FCM enforces the presence of "aps.alert", developers are forced to include dummy or empty alert values (e.g. "alert": {}), which can still cause unwanted side effects or violate Apple’s Live Activity design guidelines.