Same Settings, Different Results

Hello,
I'm new to FF and just starting to experiment. One issue i'm running into is that it is sometimes impossible to replicate my results, even when using the exact same settings. For example, i'm using Blur Shift, and liked what I got, but then I make a small color change on the upper left of my raw image and run the same filter again. But then it changes the details throughout the image. Almost as if the settings have been changed. My distortion is only set at 1, so my small edit should remain local and not affect the whole image. Any thoughts on this?

GMM, Thank you for your reply. I thought everything was the same, but perhaps I overlooked the variation values. Thanks