When traveling from the Nether to the Overworld through a portal generated by the game, instead of coming back through the original portal, another is generated ~200 blocks away.

I thought, by going through the game-generated portal in the Nether, I would come back to the one I created.

What actually happened was the game generated a new portal about 200 blocks from the one I made. I destroyed the new portal and tried again - the same thing happened and a new portal was generated within 10 blocks of the one I had just destroyed. After trying a few more times, there were around 15 portals within 20 blocks of each other far from the original portal.

Steps to Reproduce:
1. Create a portal near where you spawn in a newly generated, standard, 1.8 Minecraft world (Survival Mode).
2. Enter the portal.
3. When in the Nether, re-enter the portal created by the game.
4. If the case is like mine, you won't return to the overworld in the portal you created - a new portal will spawn 50 - 200 blocks away from your portal.