Thank you.
I did read the Minecraft Wiki before posting. After realizing my issue, this is what I find confusing:
"An activated End Portal allows the player to enter The End immediately, appearing on top of a five by five Obsidian platform in The End. The center of this portal is always at the co-ordinates 0,72,0."
I was able to find the dragon at those coordinates, but I spawned into The End over 800 meters from those coordinates.