Hi BACA IT,
1. Please check if the windows 10 1511 clients are indeed upgraded to 1607 version, you may check the information here:

2. If the client is indeed upgraded to 1607 and the SCCM do not show up correctly with the anniversary update, please install the monthly rollup for windows 10 manually on one client for test, check if it works well after then:
https://support.microsoft.com/en-us/help/4000825/windows-10-and-windows-server-2016-update-history
3. If it still not work, please turn to SCCM forum for more professional help about SCCM with WSUS:
https://social.technet.microsoft.com/Forums/en-US/home?category=systemcenter2012configurationmanager
Best Regards,
Anne
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