If you log out and log back in whilst in the End with the Ender Dragon, it will make a copy or duplicate and all shrines will be gone. If done a second time, you will be booted from the End and will spawn in the Overworld.
MC-14391
Ender Dragon bug
Resolved
Invalid
0
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.