How to reproduce:
1. Extract and open the attached project ("IsValid bugs.zip") to your preferred workspace
2. Submit the initial project including all of its Assets
3. Observe that the "test" material is not checked out
4. Go to "Simple Window" -> "SubmitIsValid" to perform a SubmitIsValid check on the "test" material
5. Observe the console
6. Check out the "test" material and change its color
7. Go to "Simple Window" -> "RevertIsValid" to perform a RevertIsValid with the RevertMode.Unchanged on the "test" material
8. Observe the console

Expected result: SubmitIsValid does not return true for assets that haven't been checked out/modified and RevertIsValid with RevertMode.Unchanged does not return true for modified assets
Actual result: RevertIsValid with the RevertMode.Unchanged returns true for modified assets and SubmitIsValid returns true for unchecked assets

Reproduced in: 2020.1.0a2, 2019.3.0b1, 2019.2.3f1, 2018.4.8f1, 2017.4.32f1