Spurious Scans during screensave

Recently upgraded to ver 21.1.0.18 on Win 7 Home Premium (Fully up to date)

Since then after the screen saver kicks in and I "log back in" I get a notification:

 

Scan completed: Full System

Scan. Threats have been found

and fixed

 

View Details

 

1) Full Scan cannot have taken place in the ten minutes or so that the screen saver has been on

2) Clicking on Full Details show no new scan - let alone any threats resolved.

 

What is going on?