What are the reasons that the "Show block on specific pages" settings wouldn't work? I have a site with a large number of blocks, but I just added a new one that's only supposed to show on one page but it shows on every page. If I exchange it with another block I have the same problem. If I remove a bunch of blocks the problem remains.

If I put  in show on all pages except those listed, it will still show on the front page. If I only put something like about with "Only the listed pages" selected, it will still show on the front page. This is happening with different types of blocks.

I've disabled Context, and Display Suite. I've flushed the cache tons of times. What could be overriding this setting?
It turns out that the issue was that there was, at some point, a theme with the same name but with different capitalization. It looks like this led to inconsistent results when looking up which blocks should be displayed and when. Once I removed all the entries in the block table to the old theme the problem was resolved.