Post and Page revisions "missing"

Ok I’ve been all over the place looking for a clue on why this is and I haven’t been buy one, a clue that is.

So my issue is that on a blog post or page I don’t have the ability to check the revisions box on the screen options tab. Its just not there for me to check.

I’ve done all the standard WP things, disabled all plugins, reverted to a stock theme, re-installed core WP and I get the same old nothing.

Yes i’m aware of putting the following in wp-config.php

define( 'WP_POST_REVISIONS', true );

but doing that doesn’t seem to matter a bit. I found some reference that the above should be placed before

require_once(ABSPATH . 'wp-settings.php');

which it is and it still doesn’t matter.

I have other sites running 4.2.2 without this issue.

I’m beyond stumped.

Chuck