Post process enabled doesn't remain off once you close persona even though it's unticked

The auto exposure that occurs with the post processing still occurs even though post processing is turned of when persona is closed and reopened.

1. Compile and open the editor
2. Open a skeletal mesh e.g. SK_Mannequin
3. In the preview scene settings tab
4. Untick show environment and showfloor
5. Untick Post processing enabled
6. Close Persona
7. Reopen the mesh by double clicking on it
8. Zoom out from the mesh
   Result
   Post process enabled is turned off yet the post process effect is occurring