My first 1.9 Snapshot test world acted a little weird, so I created another one. I then went to the end, to find 2 Ender Dragons. I killed the first one, and the portal to the other islands didn't come up. Once I killed the second one, the portal appeared. I'm not sure what could have triggered this, or if randomly, 2 Dragons spawn in random worlds. I did kill the two Dragons before I could get a screenshot, so I recreated the world and went to the end again. Although, there was only 1 Dragon again.
Environment
Seed: 4866197274125695729
Linked issues
is duplicated by 9
MC-82951
If you die in the end while there is a ender dragon, a new one will spawn resulting in mulitple!
Resolved
MC-83180
in the end their was 2 dragons
Resolved
MC-83181
in the end their was 2 dragons
Resolved
MC-83687
A weird glitch with the ender dragon.
Resolved
MC-83793
Triple Ender-dragons
Resolved
4 more links
There was 2 in my world but one despawned in the middle of the fight