Code to illustrate new reloading of ScriptableObject in Unity 2019.1

ScriptableObjectReload.cs

using System.IO;
using UnityEngine;
using UnityEditor;

// Save this to a file named ScriptableObjectReload.cs and run this example with menu item "Examples" -> "Reload ScriptableObject Example"
public class ScriptableObjectReload : ScriptableObject
{
    const string assetPath = "Assets/ScriptObject.asset";
    public string stringValue;

    [MenuItem("Examples/Reload ScriptableObject Example")]
    public static void ReloadScriptableObject()
    {
        AssetDatabase.DeleteAsset(assetPath);

        const string initialValue = "Hello";

        Debug.Log("Creating ScripableObject");
        {
            // Create asset with ScriptableObject
            var scriptObj = ScriptableObject.CreateInstance<ScriptableObjectReload>();
            scriptObj.name = "ScriptObject";
            scriptObj.stringValue = initialValue;

            AssetDatabase.CreateAsset(scriptObj, assetPath);

            AssetDatabase.SaveAssets();
        }

        // Load the asset with the ScriptableObject
        var loadedObject = AssetDatabase.LoadAssetAtPath<ScriptableObjectReload>(assetPath);

        if (loadedObject != null && loadedObject.stringValue == initialValue)
        {
            Debug.Log("Successfully loaded newly created ScripableObject");
        }
        else
        {
            Debug.LogError("Failed to load newly created ScripableObject");
        }

        Debug.Log("Wait before modifying ScriptableObject to ensure modified asset file timestamp is more than 1 sec different");
        System.Threading.Thread.Sleep(1100);

        Debug.Log("Modifying ScriptableObject as text file");

        const string modifiedValue = "HelloWorld!";

        {
            // modify the asset file on disk
            string text = File.ReadAllText(assetPath);
            text = text.Replace(initialValue, modifiedValue);
            File.WriteAllText(assetPath, text);
        }

        if (loadedObject.stringValue == initialValue)
        {
            Debug.Log("ScriptableObject not yet reloaded");
        }
        else
        {
            Debug.LogError("ScriptableObject should not be reloaded");
        }

        Debug.Log("Refresh assets");

        AssetDatabase.Refresh();

        if (loadedObject != null && loadedObject.stringValue == modifiedValue)
        {
            Debug.Log("Successfully reloaded ScripableObject");
        }
        else
        {
            Debug.LogError("Failed to reload ScripableObject");
        }
    }
}