Board Thread:Episode Discussions/@comment-25319479-20160526105603/@comment-4912646-20160526170243

It's not as though the anime made unintentional mistakes so much as they decided to change things established in the manga (and prior episodes for that matter) which is a really confusing decision. Comparing Black Zetsu's story with its manga counterpart, they deliberately removed the line about Ten-Tails being made into the core of Chibaku Tensei and changed the "even Hagoromo didn't know about this" line to be about Black Zetsu's creation, rather than the Ten-Tails being Kaguya.

In hindsight, we got a preview of this weird change a few episodes back when Sasuke thought that Hagoromo knew Kaguya would be revived. The question is why he wouldn't just tell them that though (and why the studio chose to make this change in the first place).

I guess at least with the core of the moon issue we'll have to treat the anime and manga as intentionally different. In the manga, the Gedo Mazo is Ten-Tails' husk and in the anime it's Kaguya's.