New episodes of Young Justice: Invasion will begin September 29th as expected. The new episodes will be a continuation of season 2 however, the extended episodes will be at least six episodes. This means that season 2 will probably end in November 2012. Cartoon Network has also stated this:
The run is expected to last for at least six episodes, though representatives for the network stress that the schedule is subject to change without notice. In addition to new episodes of both DC Nation programming block anchors, new animated shorts and bonus content will also return. Specific details have not yet been provided.
So, things are subject to change. Well, that’s good news. Cartoon Network probably wanted to see how well the change of characters would be for the viewers. Now that Dick Grayson has assumed Nightwing and Tim Drake has become the new Robin. Also, the addition of Batgirl and other female characters to attract more girls to the show could be a factor in why season 2 was cut short last time.
Source- World’s Finest Online