Problems with Firebase notifications anyone?

Question

I am using the FirebasePushNotification Plugin in my app (iOS and Android) and most of the time the push notifications work fine, but I found some issues.

Sometimes I can see from the logs that the notification was sent to my test device successfully:

• The result of the process says { "successCount": 1, "failureCount": 0 }
• I get the notification ID back
• The Firebase token on my phone matches the one used in the target of the push notification

But the problem is that my phone never received it.
After some testing, I came to the conclusion that when my app has been closed (full exit/kill) for a few hours (for example if i turn off the phone for some hours) I don't get any notifications even if the send was successful.

All I need to do is to open the app once, and then I start receiving them again.
It's very unreliable because some of the notifications need to be delivered whether the users are actively using the app or not.

I already submitted an issue on the plugin page but it doesn't look like i will get an answer, and it's hard to reproduce.

This is happening on Android, I am not sure yet on iOS. One question is, could some dependencies be missing?
If you look at the list here under Android, do you have to install those dependencies manually? I didn't, I just installed the plugin and figured that it would automatically install what it needs:
https://www.nuget.org/packages/Plugin.FirebasePushNotification

I've always used AppCenter notifications and they used to work GREAT! Too bad they dismissed that service!

Thanks.