How to prevent duplicate notifications in the background state?

[Felipe-OT]

When the app is in the foreground, onMessage() is triggered normally, even if the payload contains notification{...}, showing only one notification, handled by Notifee. However, when using setBackgroundMessageHandler(), both the FCM notification and the Notifee notification are displayed, which is very strange. If onMessage() prevents the default FCM notification from being shown, why doesn’t setBackgroundMessageHandler() do the same?
I can't remove notification{...} because I want to receive notifications when the app is in a quit/killed state.