World Name not updated in GUI after renaming

Hi,

I just noticed that the GUI doesn't update the name of a renamed world.

 

Steps to reproduce:

1. Load in Minecraft Snapshot 18w30b (as it did work fine in the Release Version 1.13)
2. Rename a World and hit Save
3. See that the world name did not update
4. Restart the Game
5. Now the world name got updated

 

The attached picture shows this on a renamed world.