Microsoft Graph V1 Teamwork SendActivityNotificationToRecipients Returns 202 Accepted Status Code, but Activity Feed Notification Is Never Received in Microsoft Teams

I am attempting to use the Microsoft Graph API to send Activity notifications to recipients in Microsoft Teams. (Using this documentation https://learn.microsoft.com/en-us/graph/api/teamwork-sendactivitynotificationtorecipients?view=graph-rest-1.0&tabs=http) I am using the application TeamsActivity.Send permission.

When I call the bulk notification endpoint via the Graph API, I get a 202 Accepted response. However, the activity notification is never posted to Microsoft Teams.

Here is an example request body with a single user with my app id and user ids removed. I am including my Graph token in the authorization header and have verified that it has the TeamsActivity.Send permission in the roles claim.

{
    "topic": {
        "source": "entityUrl",
        "value": "https://graph.microsoft.com/v1.0/appCatalogs/teamsApps/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
    },
    "activityType": "systemDefault",
    "previewText": {
        "content": "Internal spending team has a pending finance approval request"
    },
    "recipients": [
    	{
        	"@odata.type": "microsoft.graph.aadUserNotificationRecipient",
        	"userId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
    	},
		{

        	"@odata.type": "microsoft.graph.aadUserNotificationRecipient",
			"userId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
		}
    ],
	"teamsAppId": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
}