Whenever I mount my company chocobo, it says I mounted whatever the last thing I targeted was. Be it a mob, an npc or a pc.

For example, "Tiri Thon mounts the Mamool Ja Breeder" or "Tiri Thon mounts Mamoodi"

My chocobo's name is BigBird, but according to the text I haven't mounted him once yet in ARR.

Edit: PS3 version.