Final Update: Wednesday, 04 December 2019 13:07 UTC
We've confirmed that all systems are back to normal with no customer impact as of 12/04, 03:03 UTC. Our logs show the incident started on 12/03, 18:00 UTC and that during the 9 hours 3 minutes that it took to resolve the issue customers who have configured the Activity log alerts in US Gov Central/East Region might had experienced alerting failures.
Root Cause: The failure was due to an issue with one of our dependent service.
Incident Timeline: 9 Hours & 3 Minutes - 12/03, 18:00 UTC through 12/04, 03:03 UTC
We understand that customers rely on Activity Log Alerts as a critical service and apologize for any impact this incident caused.