Avast Free Scans do not run when scheduled

Have used Avast Free for many years, always ran well. Recently however, scheduled scans sometimes run when scheduled, but often either do not run when scheduled or start some hours later. Have Repaired Avast and Uninstalled/Reinstalled, but still happens. Anyone else experience this? What is the fix?

I have seen the same thing on my desktop. But my laptop always runs at the scheduled time.
When I notice that it has not started on my desktop, I just go into the settings and change the start time to the next minute or two. Then when it is finished with the scan, I go back and reset it to the original time, (just in case it works the next time).

This is on a laptop. I believe I have tried changing times, but will give it another try.