Tiling is messed up!

[BlueStag]

So I was messing around with a 200x200 world created in TEdit. However, when I built a house for the guide, left the world and joined back in, the tiling was messed up. I wanted to do some experimentation first. Keep in mind that I have no idea how slopes work in this game.

Experiment 1. Is copper brick the only tile that's affected?
I built a sculpture made of copper brick (the material I used to make the house) and dirt and it looked like this:

When I rejoined, it looked like this:

The block on top of the right door looks normal because I opened it. There are some things that have happened to the copper brick part:

1. All the square tiles look the same:
   
   . This is the first tile in the tileset.
2. Each square tile is offset by 1 pixel in both axis:
   
   .
3. The sloped tiles do not use a correct texture:
   
   . I don't know how slopes work in this game.

As for the dirt, it has not changed. However, the top four copper brick tiles have not been effected, which leads me to my next experiment...

Experiment 2: If only a few were affected, does that mean that dirt can be affected?
I decided to switch the materials around. This is what it looks like:

I reloaded the world and this happened:

So dirt can be affected. But...

Experiment 3: How many rows are affected?
I built this tall sculpture to test it:

Upon reloading the world, part of it got affected:

Only the first seven rows get affected. I'd like to remind you that this is a 200x200 world, so...

Experiment 4: What happens in a normal world?
I created a fresh new Journey Mode world, and built this right at the bottom of hell:

However, it did not change after reloading:

Remarks
I believe this happens because Terraria gets lazy with its tiling when it reaches beyond the edge of the world. However, I was standing ON the edge. When I looked in my map, I saw that I was placed under the sky. Here's all the experiments together, including my house:

I'm not sure if this will work, but look at the attachments below for a world download anyways.

-- BlueStag --​

 

[Simple🌳]

This is a very interesting thing that more people should look into. One thing I find very interesting is that the tiles are only affected when they are placed at a certain height. My guess is that this is the result of an error in how the code handled number values for this world?

I am confused about how you stated that it was a 200x200 world, since Terraria's average large world is 8400x2400 blocks.