Seems to have fixed it.
I would recommend all doing a full/custom scan on everything.

When I found the scans were broken, I started scanning folders, Windows-passed, program...

Windows Defender quick and full scans will not fully scan all files ("Scan now"), I get report 14 files scaned, before scan stopped which took a few seconds. If you do a custom path scan, for example...

I didn't try altering just those and hitting "checking for update". I only found first doing those two only brought back the field until next reboot, so I compared known unaltered 1903 PRO reg and...

What I did to reset back to 0 days is check the two reg keys "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsUpdate\UpdatePolicy\PolicyState". I added comments to action taken....