PDFs not syncing

Hello. I tried to share a library with a colleague using the sync feature + EndNote online. But we are facing a few challenges. I wonder if you have any suggestions

  1. The library syncs, but the PDFs do not (they are uploaded & synced to EndNote online) - how can I ensure the PDFs in the library sync as well?
  2. If I share two libraries and would like them to remain separate - they merge into one - is there a way to sync libraries with collaborators without merging libraries?

Thank you!

Radhika