I have the same issue as Namow. I lost the default GC barding from my chocobo that came from 1.0. As soon as I equipped the behemoth barding, the GC barding disappeared. I can equip and unequip the behemoth barding, but the GC barding is no longer in the list. Some things to note for my case, the barding was Limsa's Maelstrom GC from 1.0. In ARR, I joined Ul'dah's Immortal Flames GC. Not sure if that would cause any problems.