Comment Section – Topic not translatable

I recently updatet from Version 1.7.1 to 1.8.5 and noticed the new comment section.

I do love the new design, however it seems like I am not able to translate certain strings (for example the header):

Has anyone run into the same problem?

Where do I translate that certain string?

Is my .pot-file out of date? (1.750 strings included)
If yes: Where do I get the updatet version?