When upgrading any 1.18.2 world to 1.19 the end generates with weird chunk borders likely caused by the world blending. Since I created this world just to check if it wasn't a modded issue i can confirm this was done 100% vanilla
To recreate:
make a new world in 1.18.2
Go to the end and fly to the outer islands or /kill the dragon and go through the portal
Fly around a bit to load chunks
Quit Minecraft and start Minecraft in 1.19
Go to where the world would upgrade terrain (generate new chunks)
Linked issues
duplicates 1
Attachments
Comments 6
This may qualify as a duplicate of MC-243089, which was resolved as "Works As Intended"; according to that ticket, chunk blending is only supposed to work for the overworld.
I think its different as with 1.17 to 1.18 the entire world generation engine was changed and therefore the way the end and nether generate changed. However now nothing has changed from 1.18 to 1.19 in the end and nether. As you can see in the screenshot, it just generates a tall wall (2-3 blocks) for no reason and then it continues to be the terrain it would have been.
generate the same seed once in 1.18 and once in 1.19 to confirm the terrain would have been the exact same in both versions:
[media][media]I think the main problem with these versions is that it seems to apply some kind of blending (without intention) and that causes the weird borders. The terrain is unchanged yet it tries to blend. This and MC-252511 do seem related with that matter.
Dupe of MC-252511
World download: https://mega.nz/file/hl1WDboI#bD1gCNZ5og7m_tx6GyMmlMat0E0-cBkNm9XoQJV811o