Hi Stu, thanks for posting.
I'm not able to reproduce this one - I just now edited a page externally and synced the changes from the sync button when viewing the page, and then did the same from the sync button in the pages index, and in both cases it worked well.
Are you sure it was editing the page externally that caused the deleted message? Did you rename the file when you edited it perchance? Have you emailed any content to that page?
Mark