Hallo,
every time I share a post on Google+ social network, Avast add a few blank lines to my post ending with "WebRep" and something more i can't remember at the moment. Editing the post to delete that lines fixes the issue.
Could you please investigate a little more? It seems a problem related to WebRep plugin. I'm usign latest version of AIS 6.0.1289 and Firefox 7.0.1.