htaccess just stops working all off a sudden

[rpjones007]

I'm using Apache Basic Authentication (htaccess) to protect a subdirectory within my website. I can't figure out why, but occasionally (every couple of weeks), the authentication seems to just stop working. I manage the server myself, so I know there are no server side changes. I can't figure it out.

In order to isolate the problem, I turned off AllowOverride:
AllowOverride None

So, rather than using .htaccess file in the directory, I moved all of my directives into the main /etc/httpd/conf.d/site.conf file:

<Directory /imsure/

http://www/php.ryanpauljones.com/steamers/admin>

AuthName "Admin Console"
AuthType Basic
AuthUserFile /imsure/htpasswd/php.ryanpauljones.com/steamers.htpasswd
require valid-user
</Directory>

There is only one user in the steamers.htpasswd file. For a while, it will be working just fine, and then for some unknown reason, it will just stop authenticating. The authentication window still comes up, but the user and password stop working. I can change the password at the command line and reload apache, but it still doesn't work.

The even weirder thing is that if I go into the /etc/httpd/conf.d/site.conf file, comment out the entire section that I listed above, and restart apache attempting to disable authentication altogether, the authentication window still comes up. I can't even disable authentication.

This is killing me right now. Any ideas would be greatly appreciated.