Maybe she just needed to make some of that stuff she and Pipp made a while ago. Sure, it was to revert Izzy, Hitch and Sunny back into adults after Pipp used alicorn glitter, turning them into foals. Perhaps Pipp was experimenting with alicorn glitter again.
(Note: In this AU, most TYT episodes have happened. But “Baby Critters” and beyond has never happened and won’t happen)