Failed to load chunk

[RevolvingMadness]

Describe the bug
When I edit a world and then load it with Minecraft, for some chunks I get a message saying "Failed to load chunk [x, z]. The blocks that I modified are there but the rest of the chunk is not..

To Reproduce
Steps to reproduce the behavior:

1. Modify a world
2. Load the world
3. Some chunks will give an error message

Expected behavior
The chunks should load with the modified blocks

Screenshots

Desktop (please complete the following information):

• OS: Windows
• Program Version ??? (Where do I find this?)
• Minecraft Version 1.21.1
• Java Version 21

Additional context
The log error is:

[17:04:43] [Server thread/ERROR]: Failed to load chunk 30,122
java.lang.ArrayIndexOutOfBoundsException: null
[17:04:43] [IO-Worker-23/ERROR]: Negative index in crash report handler (0/4)

[gentlegiantJGC]

Can you attach an example world.
Did you paste into chunks that had not been created yet?

[RevolvingMadness]

I used chunky to generate the chunks so they should've been generated..

[gentlegiantJGC]

Can you attach an example world.