Info / Apps / Sec. --- Windows Defender was unable to complete the update 0x8024002b

In my experience, the problem is caused by the SUS registry key.
You should remove SUS registry (Take your own risk) by remove following key "HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\WindowsUpdate" and run WindowsUpdate manaully, then your defender will keep up-to-date.
Ensure your WindowsUpdate is enable and scheduled to run
Start from 2006 ...