How to reproduce:

1. Open new project
2. Create a single Capsule game object and attach a Rigidbody component to it
3. In the Rigidbody, enable the Rotational constraints on the XYZ axes as well as the positional constraints on the Z axis
4. Create a new script and add the following code to it:

void OnGUI()
{
if (GUILayout.Button("Deactivate!"))
{
var rb = GetComponent<Rigidbody>();
rb.centerOfMass = new Vector3(0, 0, 0);
gameObject.SetActive(false);
}
}

5. Save the script
6. Attach the script to the Capsule and run the scene
7. Click the "Deactivate!" button in the top left corner
- This error is thrown: "Inertia tensor must be larger then zero in all coordinates."
- The error can be safely ignored for now, as it is harmless. It simply means that a check is performed during deactivation when it is not supposed to be, and the check results in this error.