I just realized I have been using the same UUID for MULTIPLE books because I created a template in Sigil that I use to start formatting every new release.
Also, I typically save the file for each individual book five times with a different file name after updating buy links and "other books by me" links (Amz, B&N, Google, ibooks, smashwords, kobo) and the UUID is the same for each version.
1. Do I need a different UUID for each version of the same book on different platforms?
2. Do I need to go back through all my books and republish the epubs with new UUIDs?
I'm feeling green at the very idea of it.

Ava Bradley