Dictionaries don't serialize within scriptable objects

Hello. I've been working on the problem of dictionaries within scriptable objects. The most common solution of making a non-generic dictionary that implements ISerializationCallbackReceiver doesn't actually seem to work for me. When I use the Asset menu to create a new ItemTemplate (which is scriptableobject) and then start/close the Game view, because the deserializer sees nothing within the Lists within the SerializeableDictionary it wipes everything.

Here's the relevant code:

This is the ScriptableObject:

 public class ItemTemplate : ScriptableObject
 {
     public SDict_StrStr tags_string;
     public Dictionary_StrInt tags_int;
     public int test;
     public string nametest;
     
     public ItemTemplate()
     {
         tags_string = new Dictionary_StrStr();
         tags_int = new Dictionary_StrInt();
     }
 
     public void setTestTags()
     {
         tags_string.Add("name", "base herb");
         tags_string.Add("description", "It's a base herb.");
 
         tags_int.Add("basecost", 100);
 
         tags_float.Add("volume", 5);
         tags_float.Add("trait:base", 1);
 
         tags_bool.Add("isPlant", true);
 
         test = 8;
         nametest = "base herb";
     }
 }

This is the SerializableDictionary:

 using System.Collections;
 using System.Collections.Generic;
 using System;
 using UnityEngine;
 
 
 // adapted from http://answers.unity3d.com/questions/460727/how-to-serialize-dictionary-with-unity-serializati.html
 
 [Serializable]
 public class SerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, ISerializationCallbackReceiver
 {
     [SerializeField] public List<TKey> keys = new List<TKey>();
     [SerializeField] public List<TValue> vals = new List<TValue>();
 
     public SerializableDictionary() {
     }
 
     public void OnAfterDeserialize()
     {
         if (keys.Count != vals.Count)
         {
             throw new ArgumentException(string.Format("{0} things in keys and {1} things in vals. Mismatch."
                 , keys.Count, vals.Count));
         }
         for(int i = 0; i < keys.Count; i++)
         {
             Add(keys[i], vals[i]);
         }
     }
 
     public void OnBeforeSerialize()
     {
         keys.Clear();
         vals.Clear();
         foreach (var kp in this)
         {
             keys.Add(kp.Key);
             vals.Add(kp.Value);
         }
     }
 }
 
 [Serializable]
 public class Dictionary_StrStr: SerializableDictionary<string, string>, ISerializationCallbackReceiver
 {
 }
 
 [Serializable]
 public class Dictionary_StrInt : SerializableDictionary<string, int>
 {
 
 }

The serializer does serialize primitive fields like int/str within ItemTemplate, so it's being serialized. Just not completely. How can I make the dictionaries within ItemTemplate be serialized?

Also, could the fact that I'm using a MenuItem to create ItemTemplates be the problem? The code is like such:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
 
 public class MakeItemTemplate {
 
     [MenuItem("Assets/Create/Item Template")]
     public static ItemTemplate Create() {
         string path = EditorUtility.SaveFilePanelInProject("Create new ItemTemplate",
                         "NewItemTemplate.asset",
                         "asset",
                         "Please select file name to save ItemTemplate as:");
 
         ItemTemplate asset = ScriptableObject.CreateInstance<ItemTemplate>();
         if (!string.IsNullOrEmpty(path))
         {
             asset.setTestTags();
             AssetDatabase.CreateAsset(asset, path);
             AssetDatabase.SaveAssets();
             return asset;
         }
         return asset;
     }
 }