This means if you go to Settings -> Update & Security -> Windows Update -> Advanced Options -> Choose when Updates are installed and un-check “Give me updates for other Microsoft products when I update Windows”, you won’t get cumulative updates. If this wasn’t enough, some users have also claimed that deferring the updates from settings also has a similar effect.
To fix it you need to change the days back to 0 and the cumulative updates will download right away. Right now Group Policy incorrectly blocks all the security updates if you change the days to anything apart from 0 days. You can set days ranging from 0 to 365 days according to your needs. In case you don’t know, you can delay the updates by going Local Computer Policy > Computer Configuration > Administrative Templates > Windows Components > Windows Update > Windows Update for Business > “Select when Preview Builds and Feature Updates are received”. As per the reports, Windows 10 Fall Creators update blocks the security updates if a user delays installation of updates in the Local Group Policy. Now many users are reporting issues with this feature on the Microsoft TechNet forum. This feature is useful for Windows Administrators or even users who want to delay the installation. With the introduction of Windows 10 Fall Creators Update, Microsoft added a new feature that allows users to delay the installation of Windows Feature updates for up to a year.
Update: As per the latest update we got from Microsoft, the bug has been fixed.