This problem happened 5 months before Windows 10 version 1909 was released. So upgrading to Windows 10 1909 wasn’t an option. It also would not have solved this issue.
The reason I identified this problem is due to the fact I had two identical instances of Windows 10, running two different builds, of Windows 10 version 1903. I noticed one install had the options, and the other did not.
I recently ran into an issue, with my legacy system, at the time I had the problem it was running a build released before May 29, 2019.
When attempting to update the legacy system I noticed the option to defer feature updates and quality updates was missing. I had manually performed the update to
Windows 10 version 1903 using the upgrade assistance, in an attempt to solve a problem, I had with a .NET Framework application.
At the time I was running two Windows 10 installation on two different systems. One was a clean
Windows 10 version 1903 installation while the other was
Windows 10 version 1809 which I manually upgraded to
Windows 10 version 1903 in order to solve the unrelated problem.
I knew something was wrong when the legacy system didn't display the deferment options yet the new system did.
Why are options to defer feature updates and quality updates missing from the Advanced Windows Update options? The system had previously been running 1809 with those options set to 60 and 30 days respectfully.