I have noticed no problem with FF 29.01 or any other FF version prior to this.
Are we sure that the problem is actually a problem?
For obvious reasons any web site that comes up in a search result that hasn't been rated by sufficient numbers of AVAST WebRep users will mean no WebRep icon will be present. If you go to the unrated site the main Toolbar WebRep icon will grey out.
I'm not sure how many people have to rate a web site for the WebRep rating to work but, for example, I'm on several very well populated forums which have existed for more than a decade. I submitted a WebRep rating for them when the feature was first provided. They're still not showing any rating. There's just a greyed out WebRep icon which I've always assumed is because there simply aren't enough AVAST users of the forums who have bothered to rate it themselves.
Are we sure that isn't what is being seen here and the simple explanantion is it is because vast numbers of sites haven't been rated by WebRep users?