MLP Tell You Tale "Moon Festival"
I'm wondering if this is meant to mimic the real life Chinese Moon Festival?
In this episode they mention that the every ten years the moon is at its closest to the planet. With TYT it can be difficult to tell if something is lore woven into the setting or a one-off idea.
(Like I saw a lot of people going "What does it MEAN" over the TYT episode where Sunny's dad left her clues to a mysterious rug / tapestry . . . but I don't think it had any deeper significance than the writers going "Hey, a short based on The Da Vinci Code, where they follow clues, would be fun." That's literally why it's called "The Starscout Code".)
But if this does tie into the deeper lore, that would be interesting. We have had Princess Luna referred to in Make Your Mark.