Pagination block is inaccurate

[esiao]

The pagination block (located in navbar here) is inaccurate

It first seems that it changes number when post is visible but that's not always the case. And when you try to access a specific post (works) the number displayed is the one of the lower post.
I guess in term of logic it should be when the post is a the top of my screen it becomes current one. But the problem is with the last ones that will never reach the top of the window. I don't really see a perfect solution here but that's kinda annoying.