I am animating comps in After Effects CS6, and I'm quickly moving objects across the screen using positioning keyframes and changing size using scaling keyframes.  Most of the time it works great; but sometimes the motion blur effect keeps appearing *after* the object has stopped moving.  Not just for a second -- but forever.  It appears correct when scrubbing on the timeline, but when I render the final output movie, a non-moving object sometimes has motion blur all over it. 

Sometimes I can fix it by un-parenting some layers inside the comp...  other times it doesn't fix it.  Sometimes I just delete it and start over and it works.  Seems more like a bug then something I'm doing wrong, but this is driving me crazy and is really slowing my work down, so I was hoping somebody else had come across this and knows how to fix -- or if it's a bug, if somebody knows if and when an update is coming out that would be fantastic!

I can't find any reference of anybody else having this issue on the Adobe forums or through Google searches...  I also tried on my Mac Pro tower and Macbook Pro laptop in case it was a graphics card issue; it isn't, the exact same problem manifests itself in both areas.  I did just discover that turning continuous raster OFF does seem to fix the problem--but then my vector images are blurry when I zoom in...  and that again sounds more like a bug, not like an incorrect setting. 

I tried calling Adobe, but they told me to post here.  So here I am  

Also, this might be helpful... here is a screen capture of what I'm talking about...  I have this character, and she was on the right side of the screen.  I just moved her position from right to left with motion blur enabled...  and it looks perfect on the timeline, but then when I render the video, it looks like this when she stops moving.  And not just for a second...  I haven't animated her any further and she's just like this for the rest of the entire movie; the effect never goes away.

Thanks in advance,

Sean