The final page of Bleach chapter 509 confirms my speculation. The Juha Bach currently residing in Soul Society wasn't in fact the real villain Buckbeard.
This entire chapter confirmed it. Remember, when we were first introduced to Buckbeard he was a ruthless leader, he killed his subordinates with ease and no regret. Once he learned that Zanka No Tachi South replaced the souls of the dead with former subordinates he refused to attack.