On Android 8.1 devices, when the Android app is open or still running in the background, it receives notifications. No problem here. The problem is that when the app is killed then it never receives push notifications. The OnMessageReceived method doesn't even called (I know because I have device log line in it).
This doesn't occur in 8.0 devices. Only happens if the device has 8.1 installed. I don't have an Android 9 device so I haven't tested on 9.0.
By the way, I did the Oreo channel modifications but it didn't help.
Is there a solution or even a workaround for this problem?