Elytra does not work in the Nether

The Elytra does not work in the nether.

I teleported through a nether portal, and wanted to fly with the Elytra.

It didn't work. Also in crative mode i just fell down and couldn't glide.

Reproduce:
1. put on an Elytra (/give with unbrakeable - I don't know if that's important)
2. go to nether
3. try to glide