I got a report in the Japanese forum that claims both Web Shield and Secure DNS caused this problem.
And what is causing the same issue in other antivirus? Avast is not alone here...
Win 10, of course...
But Avast have to fix this before Win10 stable build get released, or there will be a mess.
"Slow" ring beta also has this issue, I doubt Microsoft will do something about this considering the remaining time.