I want someone from Avast to address this issue. This is silly, the transmittal is coming from their system and is annoying.
I'm not from avast, but an avast user just like yourself - If this is DNS Hijacking as has been suggested on the malwarebytes forum, then this is somewhat different when saying who is at fault.
Are you aware what dns hijacking is, when your computer/browser tries to access a site that is shown in a user friendly/readable form such as su2.ff.avast.com it checks against 'your' DNS server commonly provided by your ISP to get the IP address.
If that DNS has been hijacked then it can return a different IP address, which could be considered malicious. But if it is your ISPs DNS server that has been hijacked then they have to resolve that. This is why not everyone is effected by this and why the suggestion to change your DNS server resolves this problem, when nothing has changed in avast.
So it isn't as clear cut as you might think.