I downloaded a long movie and clipped it down to only the sections I like. I placed the clip in a shared folder for Limewire and deleted the movie from my PC.

The clip immediately got attention and the uploading was going swell when I noticed that the upload identified it with the same number of MB's as the original download. Plus the estimated time was appropriate for a complete movie at the kb's being transferred.

Yet my clip was substantially smaller, less than half.

I'm suspicious that my clip retained the old identification and my upload was a part of the shared uploading for the old movie.

Can anyone explain why the clip did not stand alone and how I can make it have a unique identity?

Interesting bug. Go to your Library window, find that file, hover your cursor over the file. Is the file size & details the new or old? Did you refresh your Library or restart LW after re-adding the file? (turn on extended tooltips .. ie: right-click the heading bar of the library & choose to show ext. tooltips; example of how to do this on the download window: http://www.gnutellaforums.com/335192-post4.html; you can turn on ext. tooltips on all windows including monitor window)

Which version of LW are you using?

I am aware of a similar bug with LW. At least for descriptions & also for id3 tags; showing incorrect information.
(On that topic, my LW thinks an mp4 (H.264) video is an audio file when trying to describe it, despite mp4 is not listed in the audio extensions, but is in the video extensions of sharing options. I had to custom describe it adding a video description under advanced describe options.)

Your bug would be worth reporting to LW. Create a new issue at this site: https://www.limewire.org/jira/browse/LWC (you will need to register there)