Hello AP. First let me say that "I do Not work with Microsoft" and, I to also lost my items a year ago after 1803 to 1809 update and boot also. you could Try this because sometimes it isn't even in Windows.Old Folder...
It may have lost control of File History and Backup! Use PowerShell to find out what is going on with your Backup and Run this command:
Get-ControlPanelItem Back* | Show-ControlPanelItem ...see if it finds it?
Also, read theses articles @: https://www.backup-utility.com/windows-10/recover-lost-files-windows-10-8523.html
Lord Bless and help you, Michael.