You understand that will make my problem worse, right?
When I post my URL I use the modified case. The only time anyone will actually visit my blog using the lowercase version is if I have forgotten to modify it or they happen to type it in manually. And then they will only be effected if they happen to then scroll to the bottom of the page and use that Older (or Newer) link.
If I change it then everyone who visits my blog from one of these links will find that link broken.
Currently this issue is not likely to effect very many visitors. If I change the case it will have the potential to effect nearly all of them.
Beyond that, the proposed workaround ignores the fact that something is clearly broken. If this problem were effecting all the links WP generated then I could see things differently. But it's only this one (or two) links. Something is wrong with the code used to generate those links and only those links.
This really looks like a bug. Probably very minor and not likely to effect many users, but equally likely very simple to track down and fix.