It shouldn't do as its just an iframe, if that were the case then every site that that used addthis would have a problem (which I know for a fact isn't true as two large sites I work with use it and have no issues).
As far as I'm aware, iframes do not pass on any of their attributes through to a website showing an iframe. The main reason I was curious about your reply was that screaming frog hadn't had any issues, I can understand myself having a small slip up, but a bit of software rarely does.
Back to the original question though, it is curious why there's no indexing by Google, Bing seems to have picked it up, and three days ago atleast. i can't see reason (in my brief look earlier) as to why it shouldn't be. So I came to the conclusion it hadn't been crawled or it had incredibly poor content (which I can't verify as I don't know Norwegian)