Edit: (because of “You have reached the reply limit for this topic”)
I debugged a bit further, and I think it’s because of Fanboy’s Annoyance List and Fanboy’s Social Blocking List. The rules that block these elements are ##.ss-social and ##.social-link (both in both lists).
If I deactivate those two lists, everything works as expected.
Posting again, since I added the filters which block the elements to the last post.
(Wasn’t allowed to post yesterday because of a limit with new posts.)
I think these two class names often get used together with the “Share with [any social thing]” buttons at the end of each site.
(And these two lists want to remove such social sharing elements.)
I added an exception for onename.com, works as expected.