On November 11, 2020 a licensed version of Macrium Reflect was supposed to run an incremental back up at 21:00. 

On completion it sends an email reporting on status.

On November 12, 2020 my client was checking his email and did not receive one from one of their machines, they have two, each backing up to their own external. They escalated to me. Not being sure if the backup had difficulties or if there was an issue sending the email I asked the client to open Macrium reflect so we could check log. 

As soon as the app was opened the Backup initiated. There was no log entry for November 11, 2020 at 21:00.

The machine was not powered down on the 11th although it would have been asleep at 21:00. 

I updated the version of Macrium to 7.3.5321 and asked the client to call me if the scheduled event for the evening of the 12th was missed. 

Has anyone else experienced something similar? Any ideas as to what might have happened? 

Here is a pic showing the daily runs and the gap on Nov 11/20