Elytra not Activating in the end

Put the summary of the bug you're having here

What I expected to happen was...:

1. get to the endgate and go to the other part of the end
2. the elytra would engage when I pressed space
3. Kill the enderdragon and be able to go to the overworld

What actually happened was...:

1. The endgate teleported me back to the obsidian platform in the main part of the end
2. I fell to my death
3. I had to /kill myself**

Steps to reproduce...:

1. Get a computer with the same specs as listed above (or not, I'm not a computer scientist)
2. Go to the end and kill the dragon
3. Exit and Save
4. Try to go through the endgate and engage an elytra