"Could not make DefaultGameplayTags.ini Writable" toast when adding to Gameplay Tag Table List Array

When adding an item to the Gameplay Tag Table List array in Project Settings, the user receives a toast reading:

"Could not make ProjectPath/Config/DefaultGameplayTags.ini Writable"

I didn't see this in QAGame but it occurred for me in a Template project.

1. Launch UE4Editor.exe.
2. Create a new blueprint template project and open it in editor.
3. Click on Edit > Project Settings.
4. Select GameplayTags on the left.
5. Click the + button for Gameplay Tag Table List.

RESULT:

Toast pops up reading "Could not make DefaultGameplayTags.ini Writable"