Trying to show a list crashes (But it's weird)

[Picklebasho]

When making a project in the editor, I came across an error: When I clicked "Show List", the stage showed this:

What does this mean? How can I fix this?

Steps to recreate (fully tested):

1. Open an empty Penguinmod project.
2. Make a list.
3. Click on "Show list"

I would like to note that this was tested on a school computer with the only scratch-related website blocked being extensions.turbowarp.org (for "Games"), turbowarp.org still works, but you cannot access the extension gallery due to this.

[Steve0Greatness]

Can replicate. I should note this only seems to happen with the "show list" block, and simply clicking the checkbox next to a list doesn't seem to cause this issue which means that this is a block-specific issue, and not related to the actual showing of monitors, most likely.