Way to reproduce:
1. Load or build a map
2. Go into the Mediatracker and drive a ghost
3. Place your cam wherever you want
4. Take a screenshot with MotionBlur enabled, like:

It display this after about 1-2 seconds

and nothing more. There is an other screen before (without the Mediatracker elements), but from this i can't make a screenshot from.
It doesn't matter which other option are activated or how long the duration at motionblur is setup to.
I have tested this in Valley and Canyon with the same results.
Btw. The option "Car reflects", "Sub-sample reflects" and "RayCast reflects" are not able to activate. I was only able to activate "Car reflects" at the driven ghost at "Force hue".
At the ghost options "Force light" doesn't turn lights on... ahm just noticed, that i have to use the "Light Intensity" to more then 50% to turn lights on at "Day" and "Sunset" moods.

EDIT: At the screenshot the value at motionblur wasn't only "1", i tried also "0.1", "0.001", "0.0005" and many more. Added the ending screen.