Board Thread:Episode Discussions/@comment-44197639-20191021085258/@comment-9782468-20191024152753

Amanim wrote: Kishimoto made this storyline to celebrate Naruto's 20th anniversary. There is nothing wrong with this timeline at all. This timeline is set after Naruto fail to bring Sasuke back from Orochimaru but possibly before the Fuma clan arc.

Also Naruto as a 12 year old is the part 1 timeline whereas Naruto as a tall 15 year old is the Part 2 timeline. Both timelines are completely different. Since Naruto came back from training with Jiraiya. They're different time periods, but Naruto and Naruto Shippuden are part of the same timeline.