Post Processing continues to affect Sprites after project setting defaults are disabled and all volumes and cameras' settings are disabled

After disabling the defaults in Project Settings > Rendering > Default Postprocessing Settings, disabling all GlobalPostProcessSettings volumes, and setting the Post Process Blend Weight in the player camera to 0, there is still some rendering difference between what's in the Viewport while editing and what displays during PIE. Using the console command, "show postprocessing" turns off whatever remaining source of post processing is going on.

This does not appear to occur with other assets, only with Sprites and Flipbooks.

Note: the difference described does not occur until after the project is closed and reopened, but occurs consistently thereafter.

1. Launch: UE4Editor.exe
2. Create a new 2D SideScroller template project
3. Drag a MyCharacter Blueprint into the level
4. In Project Settings > Rendering > Default Postprocessing Settings, disable all options and set Anti-Aliasing Method to none
5. In the Scene Outliner, delete the GlobalPostProcessSettings volume
6. In MyCharacter, select the SideViewCameraComponent
7. Set Post Process Blend Weight to 0
8. PIE
9. Note the color of sprites before and during PIE are the same
10. Save and close the project
11. Reopen the project
12. PIE

Results:
The sprites appear to have some color differences from a post processing effect, despite having turned all sources of that off. Console command "show postprocessing" will return the color to normal.

Background color & exposure in editor doesn't match PIE