I honestly think that people are just not following these instructions correctly. I had several people with this same problem and fixed it with the same solution.
Since it's difficult to follow sometimes, and everyone has made changes to their contacts you want to start completely over by erasing the contact from your address book, then making a brand new contact. leave all ringtones etc.. default. now go to your myfaves display and select this new contact to replace the one you deleted.
Now exit to your home screen. In the MyFaves display it will most likely read "T-Jingle" as custom tone.
LEAVE IT.
Exit to home screen.
Go to profiles and track down to ADVANCED
at the bottom there will be listed exceptions for alert profiles. Delete every single one of them.
Voila. now when your contact calls it uses the default ringer on your profile rather than custom.
To give a custom ringtone, you'll need to change your active profile's ringtone and then make an exception in your list making EVERYONE ELSE use a different profile.
This means a few things, most times you only get ONE tone for ALL myfaves.
But after investigating i'll say i was in the wrong about the above, this is definitely a MYFAVES Issue, when i remove the contact from myfaves and replace with someone else, i get custom ringtones but not for the myfaves.