The posts in descending order by 50 posts each page, the "d" means that when you click on page 1, you get the most recent 50 posts.

The number of the specific post you want to link to moves to the 2nd page when more posts are added, the 3rd, then... you get it. Making that link go to page "1", post "#xxxxx", and nothing happens because it's not there any more.

Better to link to a page in ascending order, because new posts get added onto the end.