Bug Configurable joint swapBodies swaps objects

Hi,
I have two objects connected with a configurable joint, using the following settings.

When I set swapBodies to true from a Start function when it is already ticked in the inspector and the linear motions are locked, it swaps the objects.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class test : MonoBehaviour
6. {
7.     private ConfigurableJoint joint;
8.  
9.     void Start()
10.     {
11.         joint = transform.GetComponent<ConfigurableJoint>();
12.         joint.swapBodies = true;
13.     }
14. }

I am using Unity 2020.3.30f1 on ubuntu.
Here's a screencap:

Is it working as intended, and I am misunderstanding something, or is this a bug?
Thanks in advance.