Massive amounts of terrain were raised into the sky, forming a wall. The land looked to be part of the biome, except it was raised massively, creating a sort of "half-mountain."

What I expected to happen was...:
I expected the land to be perfectly normal and level.

What actually happened was...:
Large amounts of land past a certain point were raised significantly higher than they should be.

Steps to Reproduce:
1. Simply walk in a certain direction.

2. Eventually, you will see the land after a certain distance.

It should be noted that the world I encountered this issue in was not new.