I don't know where you got the link to "recommend to friends" from, I couldn't see that in my.avast.com account.
The Recommendations is still in the drop down menu on my.avast.com, but probably should be removed. As the rewards function has been over for some time. I copied and pasted my referral link and it works just fine, see attached image.
My guess why it is still there is for those who may already have qualified previously as they can still get any reward they were entitled to.