When I check the Motion Blur box on a composition that on which I keyframed scale, so it scales out, on the very last frame the Motion Blur stopps working. It's there until that very last frame. This has never happened in years. I opened a new project because I thought maye be file was corrupt but it still didn't work in that new project file. The 2 pictures are the 2 last frames of the comp I'm trying to do a zoom out effect on. I've done this same zoom out effect a million times now and this has never happened. All help appreciated.
Set your Comp's Shutter Phase to be -1/2 of the Shutter Angle - this helps to mimic common realworld camera settings for creating motion blur. If you require a higher Shutter Angle then set the value accordingly but ensure you set Shutter Phase to a negative value; ideally stick to incremental values of 90.