User blog comment:Xilinoc/Ch. 608 - whatever the title of this one is/@comment-24726378-20141204151601/@comment-5398287-20141204152853

Not necessarily. If the Medallions simply gave the stolen Bankai to their wielders, then it might be; however, Zanka no Tachi is in the medallion, so unless that's directly hit by the ink, Yhwach can still use it, I'd imagine.