We've confirmed that all systems are back to normal with no customer impact as of 03/25, 12:30 UTC. Our logs show the incident started on 03/25, 12:18 UTC and that during the 12 minutes that it took to resolve the issue some customers in the East US region would have experienced misfiring alerts.
Root Cause: The failure was due to a dependent service being unavailable for a short period.
Incident Timeline: 12 minutes - 03/25, 12:18 UTC through 03/25, 12:30 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.