im a company here and providing for 10 years . have blacklisting experience since then and even know two staffs of Tea*Speak support team.
there may be some tricks to delay it but avoiding 100% is not gonna happen
its the channel bug used by some guys in back days.
its related to channel creation with invalid voice codec
disable your temporary channel creation and any way to edit channels by anyone in your server
or simply upgrade to 1.5.6