Neat Video & Neat Image community

I've a bit of a problem. I'm currently cleaning up old VHS tapes. After the clips are rendered, I get a "flash" at random. What it turns out to be is a frame from a random part of the ~clips~ is placed into a different clip in a random spot or within the same clip at a random spot. If I go back and cut out the mis-placed frame, then akk is well. But over the length of a two hour video, this is very time consuming. Has anyone had this problem in the past? If so, other than re-editing the frame out, is there a fix? I'm using the Pro version with virtualdub.
Thanks for any help you may offer.

I have never seen such an effect. Is there a way to reliably reproduce it using some small test clip?

Vlad