Automatic OS update not working

From other's experiences we know that automatic updates are not installed en mass the same day they come out. Updates are rolled out slowly across the world. So it might depend on how long you waited before checking. Automatic updates are done only at night. If your Mac is sleeping or turned off they will not happen.

Sad to report - this has been know to happen in the development of the often iffy Update Notifications.

Am not sure how to fix this apart from >>

Then have a few suggestions ;

1 - Get Support Choose a product and we’ll find you the best solution.Start now and open an Apple Support Ticket as they are Apple Employees to deal will these types of issues . 

2 - Product Feedback - Apple and make it known to Apple regarding this ongoing issue 

If you what to Bookmark this Apple Site for future reference, at least you will Know pretty quickly when something new is available

Apple security releases