chocobo rank bugged out, wont gain exp

[Palindrome3D]

Chocobo was fully capped at Rank 11, i put it in stables, fed it a Thavnarion Onion, took it out of the stables, fought a monster with it, It advanced to rank 12. And that's where it bugged out. The Rank 12 # is in Orange as if its capped, the EXP bar is empty and at 0, I can't get exp on when i'm fighting with it, and when i put it back in the stables to train it it says i need to raise the level cap before it can gain any exp, the game things its capped at rank 12 and i only just got it to rank 12.

[Mholito]

Rank 12 was already unlocked. You wasted an onion. Look at the number of start next to your chocobo's rank. Each of those stars represent the rank cap being increased by one. So, if it shows two stars, the max rank is 12, and feeding it any onions before it gets to rank 12 does absolutely nothing. Keep in mind that chocobos cannot rank up in the stables, but their xp will go up to max, so you need to take them out and kill an enemy with them for them to rank up first.
Also: you do not need to stable a chocobo to give it a thavnairian onion. You can jsut use it from your inventory.