I see, its sorted indeed. But it makes no sense to sort by score, if I change the Sort type to Top Hour. This doesn't work like a Sort type, but more like a Limit type. I would expect it to sort by time.
It doesn't work on "Overview" or "Comments", only if I limit to "Posts". So yes, it works on posts, but only if no comments are involved by Overview. Clearly this is broken. I also noticed this since months and thought I didn't understood it, then forgot about it. Now that I wanted to find a specific reply from me, I encountered this issue again.