Blur script changes Viewport rect ?

i'm a novice with unity. only just started with code. out of the box i added component - Blur optimized effect script to my FPS controller. the effect only seems to work in the Game window when i reset the camera and then it changes the Viewport rect settings so i have no vertical look movement ? i change them back to 0 but the effect won't work like this

is this a known bug in Ver 5 ? i didn't have this issue with Unity 4.

what am i doing wrong ? any help is awesome