After I set the vanilla world border, the /chunky worldborder command sets the center to a wrong coordinate and the shape to circle, even though the vanilla world border can only be rectangular. I suggest updating the chunky-shape to squared.

1. /worldborder center ~ ~
2. /worldborder set 5000
3. optional: restart the server
4. /chunky world world
5. /chunky worldborder

Chunky v. 1.3.38
ChunkyBorder v. 1.1.34
PaperMC v. 1.19.2, build 194

After some tests now the following notes:

The "issue" came from the still installed WorldBorder. Without WorldBorder it looks good. And the shape is no longer affected at all.

If "WorldBorder" manually overwrites the vanilla information, it's obviously not a mistake by Chunky. But WorldBorder is a softdepend of Chunky, so it should also handle the biggest behaviors of an installed WorldBorder plugin.

1. The information on Spigot is not entirely accurate at this point:
   

2. It might be helpful to send a message after /chunky worldborder, such as:

WorldBorder is installed: "[Chunky] Worldborder information is taken from the WorldBorder plugin data ..."
Vanilla: "[Chunky] Worldborder information is taken from the vanilla data ..."

Yes it's intentional. If WorldBorder is installed and there is a valid border to select, the worldborder command in Chunky will use that one instead, since generally speaking that would be your world border, not the vanilla one. Maybe I don't understand your use case but I can't think of a reason why you would ever have both unless you simply forgot to uninstall WorldBorder.

I agree maybe the wording on Spigot (and potentially other places) can be improved there to reduce confusion. I will take a look when I find the time. For now feel free to open a new issue if you would like to suggest improvements, but I'm going to close this one since the behavior mentioned in this ticket is not actually a bug.