Some filters get updated with the Delta Update (default of every 5 minutes).
Some filters get updated with the NS.Daily scheduled task.
And some only get updated when the user clicks the "Update Membership" button.

What is the difference?

The Delta Resource Membership update schedule will only touch filters that are associated with an active filter via a "Target’.

The Complete Resource Membership schedule will update filters that are associated with policies that are both enabled and disabled. 

Some filters have no associations with anything. They are not associated with any update schedules.

If a filter is not updating automatically, you will need to create a scheduled task to update the filter:  How to automate Filter membership updates?

Attached is a report you can import which will enable you to see what filters have not been updated in a specified amount of time (in 'n' hours).

Also attached are a couple of queries that may help you determine what filters are updating and how.

Please be advised that all attachments to this document are distributed as is and are not provided as part of the product line.