Web Browser Pull Request Diff View Doesn't Work if Source Path has Spaces

With FireFox 41.0.2 (and maybe other browsers), I am unable to view the diff of a file in a pull request if that file is within a directory that has a space in it.

For example, if I have a pull request with modifications to the files:

foo/bar/baz/whatever.txt
foo/bar/with space/sometext.txt

When I try to see the diff of sometext.txt, I'll see the diff of whatever.txt instead, even though the URL in the browser would have me believe otherwise.