Changing Xerneas Ability in PKHAX - Omega Ruby

[clecavs2]

Has anyone ever had an issue changing Xerneas' ability using PKHAX? Everytime I change it, it always reverts back to Fairy Aura when a battle ends. Doesn't seem to be effected when I withdraw/place in PC. This is for Omega Ruby - haven't tested it on other Gen 6+ games so far as it's the only one I currently have.

[Kaphotics]

That's just how the game works. Want it to be different? Figure out how to disable the changes in the ROM.

Nothing can be done with a save editor to bypass in game code.