Question dependence ScriptableObject load error.

Bundle situation:
1. Create a empty Project
2. Create a prefab asset named soldier.prefab
3. Create a ScriptableObject named SoldiersConfig, add [SerializeField] public int hp = 5;
4. Create a MonoBehaviour Class named Soldiers, add public SoldiersConfig sc;
5. Create a SoldiersConfig asset SoldiersConfig.asset
6. soldier.prefab add Soldiers Component , Soldiers Component add SoldiersConfig.asset
7. Build two bundle. One contain soldier.prefab. Another contain SoldiersConfig.asset.
8. Create two button in scene Load and Unload

load button event:
1. Load two bundle if it not loaded.
2. Load soldier.prefab asset.
3. print hp in sc.

unload button event:
1.make sure NO Managed Object reference soldier.prefab asset (soldier.prefab not used).
2. Unload the bundle contain SoldiersConfig.asset, NOT unload the bundle contain soldier.prefab.

Running:
1.press Load button, SoldiersConfig can be loaded. Got right result.
2.press Unload button.
3.press Load button again. got error:
A scripted object (script unknown or not yet loaded) has a different serialization layout when loading.


If dependence Asset is texture or material. it can be reload again when load prefab. why ScriptableObject can not?