Multisite Subfolder with Capitalization Discrepancy and Posts front page

[MadtownLems]

Multisite 3.1.3, subfolders for sites. (confirmed on nightly release as well)

mysite.com/foo has posts for a front page.

mysite.com/foo works as expected.

mysite.com/FOO loads the site foo (correct theme & widgets), but gives a 404

So it finds the site... but doesn't find the posts at the site.

[ocean90]

#16200