The Fairyversary Muffin's cameo. A quick and innocuous reference to the first movie, or Jorgen trying to give a now-fairyless Timmy an edge against the Eliminators?
Why wasn't Timmy willing to go back to Earth in the beginning of the second movie? Because on Earth, he's a bucked toothed loser boy that is consistently picked on, beaten, or considered a nobody but on Fairy World, he's a hero, he's a somebody. So it makes sense that he wouldn't want to go back to a place that treats him like a nobody.
Tying into Fridge Brilliance: Timmy doesn’t try to dispose of or take the muffin just for safety, especially knowing what could happen if it fell into the wrong hands. If it didn’t disappear like everything else afterwards, that muffin is still out there.
Trixie doesn't actually love Timmy, she is only interested because he can grant her wishes like a unicorn. As for Timmy, his mind is not erased.
Details like that never mattered before.
While we're still following Da Rules, Timmy did give away the secret of his fairies, meaning the choice was between everyone keeping their memories, or Timmy keeping Cosmo and Wanda. Perhaps Jorgen figured the only way to avoid those consequences was to strike everything from the record, and we mean everything.
This isn't the first time Jorgen's been shown to be able to flaunt Da Rules. He once tried and almost succeeded in taking Cosmo and Wanda away in Abra-Catastrophe! despite the wish using the magic muffin, which itself is made to give one Rule free wish. It's probably because, as Head Fairy and enforcer of Da Rules, Jorgen can bend or even break them if it's for the 'greater good'.
