onMessageReceived isn't always called

* Android device: Multiple devices
* Android OS version: Multiple OS versions
* Google Play Services version:
* Firebase/Play Services SDK version: 11.4.2

The onMessageReceived method is only called for about 2/3 of the users. It's not because it's in the background because it's a data payload sent from Microsoft Azure, and the method is called for me and the notification displayed when I have the app closed. I know they're reaching the device because I checked the Play Console and they're marked as 'Acknowledged'.

#### Steps to reproduce:

1. Follow the quickstart example and log the onMessageReceived call
2. Send a message with a data payload
3. See how many of your push notifications are logged

#### Observed Results:
Only about 2/3 of the notifications end up with a call to onMessageReceived.

#### Expected Results:
I expected all of the notifications to reach onMessageReceived.

#### Relevant Code:
```





```

```
public class MyFirebaseMessagingService extends FirebaseMessagingService {

...
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
...
}
```