Related posts slide in makes post content "hyperlinked"

The related posts slide in hyperlinks the post content until the first <a> in text. The text behaves like a link (hovers), but there is no link target displayed in the browser status bar.

This only happens when there are related posts displayed, if the slide in is empty everything is correct.* Also it doesn´t happen with other slide in types. I assumed that there is a non-closed link in the slide in, but checking the source code I didn´t find one.

See wrong behaviour here:
Compare this:

(* It would be more convenient to hide slide in if no related post is found.)