Yes, I’ve tested many VPN. Not all are secure as you think. There are work around for DNS Leak fix but so far PrivateInternetAccess has provided all in one solution to patch up that hole.

The fix is here but it’s not ideal for computer novice. http://www.dnsleaktest.com/how-to-fix-a-dns-leak.php

I would recommend if Avast can look into this to have an automated patching to close the loop hole of DNS leakage.