Seems like people are still receiving these FCM messages worldwide on Android smartphones on their Microsoft Teams Application.
This time around its a new one,
FCM Messages! Testing Notifcation from Microsoft to investigate this problem
It is hard to tell if this is a genuine message, but if you look at the message closely they have misspelled the Notification word as Notifcation. This really seems suspicious! When you click on this message it leads you to Teams app with nothing more to see!
There has been no details provided on this topic by Microsoft yet! Let's hope we hear something from them soon as its been over 18 hours we are seeing such messages!
Some users may receive unexpected Test notifications on their Android devicesMicrosoft has published this information in Microsoft 365 admin center --> Service Health.
The Status shows "Service restored", so we can assume there will be no further such messages.
The message reads
Some users may receive unexpected Test notifications on their Android devicesTM221041, Microsoft Teams, Last updated: August 28, 2020 12:58 AM
Start time: August 27, 2020 1:30 PM, End time: August 27, 2020 11:55 PM
Status: Service restored
User impact: Users were receiving unexpected notifications via Teams on their Android mobile devices.
Latest message: Title: Some users may receive unexpected Test notifications on their Android devices
User Impact: Users were receiving unexpected notifications via Teams on their Android mobile devices.
More info: Users may have received notifications that stated: "FCM Messages : Test Notifications" or other similar variations of this message.
Our investigation shows no indication that these messages were malicious in nature; however, we recommend dismissing any of these notifications that were received during the event without interacting with them.
Final status: We've isolated the source of the issue and applied a mitigation. We've confirmed that no further unexpected notifications are being sent to users' Android devices.
Scope of impact: This issue may have potentially impacted any user with Microsoft Teams installed on an Android device.
Start time: Thursday, August 27, 2020, 1:30 PM (8:00 AM UTC)
End time: Thursday, August 27, 2020, 11:55 PM (6:25 PM UTC)
Root cause: A configuration issue within Microsoft Teams systems that facilitate notification delivery was identified and corrected.
Next steps: - We're analyzing the configuration of the systems that manage Microsoft Teams notifications to better understand the underlying source of this issue.
This is the final update for the event.