User blog comment:Jkphantom9/RWBY Vol 3 Production Confirmed at PAX East/@comment-4010415-20150307000533/@comment-4010415-20150307143526

I figured since they talked about how they were going to have certain stuff happen in volume 2, but moved it forward to volume 3, they had some things planned. And Monty always started working on the next volume right after they finished a volume, so I figured he, and maybe others, may have gotten some things done.

Though, the only things I know of for sure that Monty had been working on was smoothing out the edges of the character models and fixing the rigging for Ruyi Bang and Jingu Bang so he could actually have Sun be useful again. The rigging for it was too complicated, and he needed to simplify it, so it'd be easier to animate Sun fighting.