“You may not pass in objects that are already persistent” error is thrown when calling Save() on ScriptableSingleton inside OnValidate()

Reproduction steps:
1. Open the attached “BugRepro” project
2. From the menu navigate to SingletonTest > Log
3. Observe the Console window

Expected result: No errors are thrown
Actual result: “You may not pass in objects that are already persistent” error is thrown

Reproducible with: 2021.3.44f1, 2022.3.50f1, 6000.0.22f1

Reproducible on: Windows 11
Not reproducible on: No other environment tested