Remove Script_CustomMS from your add-ons folder. I don't know is what it is for but it seems to make game query a 3rd party master server.
wow. okay, here was the problem. I have more addons on my v20 of BL, so I thought it was a good idea to copy all my addons into my steam version of BL. Little did I know it contained Script_CustomMS, which is exactly how you described it- a 3rd party master server meant to show v20 servers. This is what made me query the v20 servers (but there weren't any) instead of the v21 servers. Thanks Zeblote.
