We have received reports from players that harvesting Yerba Mates do not count toward the Swan Social 7/8 Quest. We are completely aware of this issue and rest assured this will be corrected soon.
You don't need to write to support about this, but you CAN click the "Fix it, Zynga" button at the bottom of this article to state that your account is affected.
Thank you again while we work on this issue. We appreciate your patience!
FarmVille 2 Support