1
My world changed.
I had a world that I made a week or so before 1.8 came out and I made a nether portal today. I went into the nether and when I came out, my map was completely different. Why did this happen?
2
What Zaphod said
I highly doubt it was a different map. You probably spawned in a different location when you came back from the nether. This has happened ever since the nether was introduced. This may never be fixed, Notch has a habit of adding more things instead of fixing problems like this.
