User targeted GPO settings do not apply on Windows 10 (1607) computers if computer is filtered

Hi

I just had a bad experience applying GPO settings to Users using Windows 10 (1607) computers.

The GPO contains ONLY settings in the USER Policies section. NOTHING in the Computer section.

The filtering shows only 2 USERS in Security Filtering section.

The GPO does not apply to those 2 USERS! Typing "GPRESULT -r" does not even list it anywhere.

- If I add the computer(s) to the filtering section, it applies.

- It applies also OK if the user uses Windows 7 or Windows Server 2012-R2 computers without the need to add those computers to the filtering section.

This behaviour is new to me.Any thoughts?

Thanks.

Thomas.