experiencing the same issues but not just with Tone Mapper, both the Interactive and full render in VFB do no respect any adjustments or changes to the camera ISO, F stop or shutter as well as any adjustments to tonemapper settings. Nothing changes in VFB even playing with extreme values like setting ISO from 100 to 10000, no change in lighting.
Tried a clean scene no dice... Updated from Corona 7 to 8, will try to uninstall and do a clean install.