User blog comment:Thailog/Ep. 207 "Depths" discussion/@comment-108.206.80.150-20120611151920/@comment-121.97.59.59-20120611155538

The hiatus is caused by Cartoon Network's scheduling. Apparently it is an American Tradition to show nothing but reruns during the summer, and an entirely new television season starts only in autumn!

Remember, folks. All twenty episodes of Young Justice invasion are done. It's too late to do anything about them. It costs an average of million bucks to make a single episode -- unless you have that money to throw to Greg and company, story changes aren't happening.

The voice acting is actually the FIRST to be done. All the animation is done with voice reference, unlike anime which reverses the process. Sure, there's probably some ADR going on to make a better sync between vocals and animation, but that doesn't require the entire cast I don't think.