How to reproduce:
1. Open the user's project
2. In the project window click Create -> What_The_Hack ModApi -> ScriptableObject dictionary
3. In the Inspector window change the Size to 1 and then set the Key to "asas" (Key name does not matter)
4. Save and Exit Unity
5. Open the project again
6. Select the SODictionary file that you've created

Expected result: You can modify the Scriptable Object
Actual result: The Inspector throws "The associated script can not be loaded." error

Reproducible with: 2017.4.22f1, 2018.3.7f1, 2019.1.0b5, 2019.2.0a7

Note: In 2017.4 versions, the Inspector does not show anything when selecting the Scriptable Object