Honestly I thought the same thing. Hearing Twilight, Fluttershy and Spike say "Cerberus" and later Twilight saying "Caillbrate" made my mind jump to Mass Effect.
She went back in time because she was visited by the original Future Twilight, who went back in time because she was visited by the original Future Twilight, who...
Look, if you guys want to argue about something, why not start somewhere that's not the basic premise for like half the time travel stories ever told (that something done by the time traveler causes the need for the time travel in the first place). How about the fact that the time spell can only be used once? I mean, I know it's magic and doesn't necessarily have rules, but come on, that's the most contrived thing I've ever heard.
I know right?! Technically in that time frame Twilight hadn't cast the spell herself yet, so the spell would still work and hence it would create a temporal loop until something happened to break it.
