>>31607369It's a non-issue. Just back up your save (if you don't have CFW now there's literally no excuse considering it takes all of 30 minutes with nothing more than an SD card reader and a step by step guide), transfer your pokemon, reload the save and everything you sent over is now safe in your bank as well as in your original save file.
But yeah, otherwise it's likely because hyper training raises the base stats of the pokemon to emulate having max IVs, and transferring that back to gen 6 just wouldn't work, because the stats are outside what those pokemon should be able to have naturally without max IVs, so it would probably flag the pokemon as hacked and not allow it online, hence invalidating any use for it in a previous generation. That and likely some altered move pools, new formes, etc. etc. There's always new stuff that just wouldn't be compatible or working as intended going backwards.
