I am not sure what you are doing to cause that problem.
Put a short clip on a new sequence. Apply the Fast Blur and max it out. Go to the end of the clip. The last frame should also be blurred out.
Put a different clip on the sequence after the first. You should see the blurred clip, then the new clip. Zoom way in to see the cut between the two clearly.
I see what you are trying to do, but i have the exact same problem as alex
Im positive when mine does it, either the effect doesnt apply on the last frame, or it takes that last frame and puts it at the start of the next clip. I am sure they are frames of the same clip and there is no timeline error, i have zoomed in and looked and checked alot.
This means i get an annoying flash of a frame from the previous clip over the start of the present one, i have restarted it and works fine, but after a while of editting, it just comes back again?
Help much needed and appreciated?