Il Community Manager Spyrian è intervenuto sul forum per chiarire che si tratta di un bug e che sono già al lavoro per risolverlo.
Spyrian ha scritto
Hi everyone, thanks for your reports!
We're working to address an issue that's preventing players from using their Lunar Rooster mounts at the moment. Don't worry if you own the Lunar Rooster, it hasn't run off! Once we resolve this, you won't need to do anything to bring your mount back, it will automatically become usable again.
Sorry for the inconvenience!
Even though we see your reports here on the subreddit, the best place to let us know about bugs you've encountered is our official Bug Report Forum.