21.9.2494 (build 21.9.6698.704) Bug!?

Since updating to this version many Windows 10 x64 files are being reported as having a virus.
If I run a full scan of my C drive there are no reported problems, but in the normal running of my PC Avast keeps advising files have viruses.
I get the same reports on a new installation of Win 10 x64 with nothing else installed.
It appears these reports are false. So how do I stop them and how can I trust Avast when it can’t find issues during a full scan that it supposedly finds afterwards?
Clearly there is a problem where Avast believes Windows normal operation is a virus!

Post a screenshot of an example.

Hi
See attachment samples for many reported windows file viruses.
If I use the explorer option to individually scan the reported files Avast reports no virus.
sfc /scannow reports no corruptions.
The files cannot both have a virus and not have a virus at the same time.
Only started after the last update.
System restore before the update, then prevent Avast updates solves the problem.

Test the file at VT (https://www.virustotal.com) and post the link to the result here.