I'm playing on a Japanese server and first thing after trying Warp (it worked just fine for me) I told my FC guys about it. And guess what? - it doesn't work with a Japanese client! None of the guys that use J client were able to use Warp.
I even linked them this link: https://ja.xivdb.com/action/10061/warp
but for them it's just another Return with a standard CD.

Isn't it weird?