Chocobo favorite food question.

So I got my Chocobo up to rank 20. He no longer needs Curiel Roots. Want to change him over to a different stat buff food for his favorite. I’ve stabled him and trained him using the new food, but it doesn’t give any indication it’s had an effect. It still lists his favorite food as Curiel Root, and while I’ve only done it twice so far I thought they were supposed to lose that if you trained them with anything else? Is it because he can’t gain exp anymore so it doesn’t register the training, or does the favorite food simply change at the full ten feedings?

Feed your chocobo the same stat food 10 times.

So after ten feedings it’ll just change with no prior indications it’s doing anything?