Apparently WordPress doesn’t have a title on title-less posts. (Duh, Twan…)
I already saw what happened with posts that have no title in readers and widgets. But pingbacks also don’t turn up right, because they use the title of a post, so it just shows “”, with no option to put in a link to the post because there is no text. Annoying.
For now I’ll just have to always use titles even posting status updates.