I’m not sure if this is a bug or an actual functionality of the ability so this might not be the correct place for this. I have 16 mounts favorited in the mount journal. 4 ground specific mounts, like Tiavan and Bloodfang Widow, the other the other 12 mounts are “flying mounts” that can also be used as ground mounts, like Crowd Pummeler 2-30, GMOD, Amalgam or Rage, and Ban-Lu; however when in an area that can only use ground mounts those mounts will never be summoned, only the 4 that are specific ground mount. I don’t know if this is a bug or not but I’d expect when you favorite a mount it would summon a mount from that total list and not segregate them into invisible categories. I have 800+ mounts and it sucks that ones that can be both ground and fly will never get summoned unless i am in an area that allows flying.