My Book Update Frequency Windows 10

I have WD Smartware set to continuous backup for My Book. Most recent Update installed.
I made changes to 2 files, added a folder with 3 files in it 2 days ago. Today I go into File Explorer and open up the My Book, went to the backup file location to insure it backed those up properly. It added the new folder with 1 file, missing the other 2 files and the other files I modified are unchanged and no new modified files added.
When set to continuous is the backup instantaneous?
Any other clue as to why it didn’t add and recognize the other files as modified and back them up?
Windows 10 64 Bit

WD SmartWare should update the backup once the computer goes into idle mode (On but not in use and not in hibernation/sleep) and pending files are not in use. Are the missing files at least displayed in the Backup Tab with an exclamation mark (Queued)?

That’s a good question that I can’t answer. I don’t’ think they were. I deleted the old backup, uninstalled everything, reinstalled and started a new backup. But before that I created a test document just in notepad to see if it would backup and it didn’t.
One thing I noticed then and now with the new backup is that any PDF file I created with the Microsoft print to PDF feature native to Windows 10 and saved is not in the backup file. One whole folder that had only those file types didn’t get sent and another folder with a few of them are missing those files. The folder and other file types are there.

Should the modified files get added to the backup queue right away and then get backed up when idle?
And to add I have it set to file backup not category. And have the whole partition checked to get backed up.

Update, modified a few files and it backed up correctly.
Glitch still there where it hasn’t added any files created by the Print to PDF. I have 1 document library with 25 items in it but only 19 show up on the My book when I open it via File Explorer.