Talk:My Little Pony Equestria Girls: Legend of Everfree/@comment-3410511-20161006145641/@comment-26423071-20161016213724

There's no indication that it "leaked magic", or that the two incidents are remotely connected.

A better argument is that, since the Battle of the Bands was broadvast worlwide, it led to an "Unmasqued World" situation, which encouraged Gloriosa to use the Gems of Harmony.

Futhermore, it's also a "ductape" effect. Midnight Sparkle's rampage stabilized the space-time continuum to the point that Earth wasn't affected by Starlight Glimmer messing around with the timeline.