Its worse than I thought. While the support technician had control of my computer, he exported Firefox's bookmarks and then imported them back. Now I have hundreds of duplicates.
I contacted Norton support. The person I chatted with said Norton Backup doesn't support selecting files or folders. Instead I have to create a shortcut for each folder I want to back up, and then select the shortcut.
I see that you added both the folder and file to your DefaultSet. What happens if you add just the folder?
I can't add the file name because it changes often.
Yeah, I had initially added just the folder as my test. Just the folder did not work. So, for testing I added the file. Then it worked that one time. Yes, I understand the file name changes.
Which is why I commented "IDK if my test is reproducible."
Are you backing up your entire Firefox profile? If so, it looks like that includes places.sqlite which contains your bookmarks. I don't know why the bookmark backups are not there, but it shouldn't matter as long as places.sqlite is saved. If you backup the bookmark backup folder separately as bjm_ did, that might work. I checked my Norton Backup Drive and \bookmark backups\ is indeed missing from a full profile backup.