How does iOS notifications handle cases without content-available key

Question

I'm troubleshooting an existing codebase where notifciations do not appear to be firing or at least are not firing to my understanding.

Things I have found in testing: Context: The feature is chat

1. Notifications will fire from the server if the chat window is open.

2. If the app is in the background or killed the notifications do not appear (the payload below is a sample payload that is being sent).

3. If I add content-available the notifications fire as they should with the app in the background. However, we're not wanting to use that key because we don't want to over extend our notification budget.

[
        "aps": [
          "alert": [
            "body": "Body Message,
            "title-loc-key": "title key,
          ],
        ],
        "source": "mySource",
        "type": "NewChatMessage",
        "unreadCount": "1",
      ]

I'm at a knowledge gap here on how else notifications would be firing without content-available.