Changes of ScriptableObject don't appear on git client's Local Changes

Question

Here I have two ScriptableObjects.

One in "TestScriptableObject.cs"

using System;
using Sirenix.OdinInspector;
using UnityEngine;

[CreateAssetMenu(fileName = "TestScriptableObject", menuName = "ScriptableObject/TestScriptableObject")]
public class TestScriptableObject : ScriptableObject
{
    public string currentTime;
        
    [Button]
    public void Change()
    {
        currentTime = DateTime.Now.ToString("u");
    }
}

The other one in TestScriptableObject2.cs"

using Sirenix.OdinInspector;
using UnityEngine;

namespace JimmyTest
{
    [CreateAssetMenu(fileName = "TestScriptableObject2", menuName = "ScriptableObject/TestScriptableObject2")]
    public class TestScriptableObject2 : ScriptableObject
    {
        public string currentTime;
        public TestScriptableObject TestScriptableObject;
        
        [Button]
        private void Change()
        {
            TestScriptableObject.Change();
        }
    }
}

When I press a button in TestScriptableObject.asset, it changes the value of 'currentTime' and clearly git client knows the change. but When I press a button in TestScriptableObject2.asset, it changes the value but the git client doesn't show me the change. I'm using git fork.

Anyone got this kind of issues before?

I want the git client to show me the changes.