I'm pretty sure that was implied.
Well, if you look at Renji's Bankai, it's kind of gotten a...thicker tail/chain thing. Like, it's first apperance, it's just held together by a chain. But nowadays his sword is basically just one giant ribbon. You could TECHNICALY say that those are a sign that "something is up" with his Bankai, but at the end of the day that's just really stupid.
He still has the worst Bankai. I remind you that he himself STILL the only person to get beaten by it.
Also, Kon being back is great. But...depends on how long he's actually back FOR.