User blog comment:ChishioKunrin/Giant Mech Fights = At Least Two Different Episodes/@comment-3257939-20140716205207/@comment-3146930-20140716211046

It is also possible these are two different fights. Maybe the robot is sent out in one episode and RWBY chase it down, but it either gets away or is captured by the WF. Then later in the season, the White Fang use it to try and do something and RWBY gets their rematch.