Domain mapping and bbPress - locked out of mapped domain admin area

I'm using the WPMUDev Premium Domain mapping plugin, and today I installed bbPress and went through the integration steps that were provided.

The last step had me make some changes to the wp-config.php file. Basically, I had to add these lines:

define( 'COOKIEHASH', 'numerical-cookie-hash-here );
define( 'COOKIE_DOMAIN', '.mysite.com' );
define( 'SITECOOKIEPATH', '/' );
define( 'COOKIEPATH', '/' );

However, I already had 3 of the lines in my wp-config file:
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');

The changes looked minimal, and everything seemed to work UNTIL I tried to login to one of my mapped domains.

Example:
blog3.mysite.com >> mapped to blog3.com

Previously, I would get to admin area by going to blog3.com/wp-admin

Now, my login appears to be broken (cannot get to dashboard) unless I go back to blog3.mysite.com/wp-admin

Any ideas why these 3 lines would screw up my ability to login to mapped domains?