Unfortunately it WAS an issue that needed to be solved. You were not supposed to have Bnet account wide TL3 and you were getting it from the Beta permissions, not permissions your char earned. I am sure your char DID earn TL3, but the forum software was not using that metric to grant the trust level.
It does not work that way for other posting chars, and is not supposed to work that way for the WoW forums. It is supposed to be char specific here and supposed to be removed if someone gets a forum penalty. It was not being done that way for people in the Beta group.
My current theory as of my first sip of coffee is about groups and how the forum prioritizes account wide group permissions over the char-server individual permissions.
The other thread is really best for this so I will just point back to the theory post there. Also, I am not awake so forgive the scatter brained thing.