The ender crystal on the pillar to the east will not be blown up after placing the 4 end crystals around the exit portal. All other crystals are blown up, then a new set of crystals is spawned. You end up with multiple crystals on the eastern obsidian tower.
MC-91581
One ender crystal is not destroyed by the dragon spawning sequence
Resolved
Fixed
2
Confirmed
ender_crystal, ender_dragon
Minecraft 15w44a
Minecraft 15w44b
Retrieved
I am sorry to say but this duplicates MC-91540. However your report contains more information so if you want you can close my report as duplicate