I don't know if this was specifically related to the 20.5 update as such, but there was new feature relating to botnet protection and the Web Shield, see
https://forum.avast.com/index.php?topic=235204.0Better botnet protection - Web Shield is even better about stopping malware from connecting to malicious servers
But it could also have been a false positive relating to that IP address, as Pondus mentioned (in the link you gave). That IP was detected in the VirusTotal link (only one, not avast) and if you checked out the other link Pondus gave, that also gave it as blacklisted IP address by a small number.
So as far as a fix goes, this was more likely to have been a correction in the Web Shield detections (virus definitions), etc.