Affects Version/s: Minecraft 1.11, Minecraft 16w50a, Minecraft 1.11.2, Minecraft 17w06a, Minecraft 1.12 Pre-Release 5, Minecraft 1.12, Minecraft 1.12.2, Minecraft 17w50a, Minecraft 18w08a, Minecraft 18w09a, Minecraft 18w16a
Fix Version/s: None
There is a math error in MapGenBase.java (MCP Name) in the generate function.
When the per chunk seeds are being generated there is a very small chance that either the x or z can be equal to 0.
When doing the per chunk math it multiplies by 0 causing every chunk in the axis to be the same.
The following seeds are affected:
There needs to be a check so that if those values are 0, then it should be set to 1.
I have recorded a video demonstrating this, including a fix: