Just confirmed that 1803 has the same problem.
latest 2018-08 updates
2018-08-14: 2018-08 Cumulative Update for Windows 10 Version 1803 for x64-based Systems (KB4343909) 4343909 Security Updates 735,492
https://support.microsoft.com/en-us/help/43439092018-08-14: 2018-08 Security Update for Adobe Flash Player for Windows 10 Version 1803 for x64-based Systems (KB4343902) 4343902 Security Updates 20,709
https://support.microsoft.com/en-us/help/4343902are missing:
Wed 08/15/2018 3:43:11.03 - Info: Starting WSUS Offline Update (v. 11.4)
Wed 08/15/2018 3:43:11.03 - Info: Used path "E:\cmd\" on REFW10-X64-003 (user: Administrator)
Wed 08/15/2018 3:43:16.76 - Info: Found Microsoft Windows version 10.0.17134.1 (w100 x64 enu sp0)
Wed 08/15/2018 3:43:16.76 - Info: Found Microsoft Windows Software Licensing Management Tool info...
Wed 08/15/2018 3:43:16.76 - Info: Name: Windows(R), Enterprise edition
Wed 08/15/2018 3:43:16.76 - Info: Description: Windows(R) Operating System, VOLUME_KMSCLIENT channel
Wed 08/15/2018 3:43:16.76 - Info: Partial Product Key: 2YT43
Wed 08/15/2018 3:43:16.76 - Info: License Status: Notification
Wed 08/15/2018 3:43:16.76 - Info: Notification Reason: 0xC004F056.
Wed 08/15/2018 3:43:16.78 - Info: Found total physical memory: 4 GB
Wed 08/15/2018 3:43:16.78 - Info: Found Windows Update Agent version 10.0.17134.1
Wed 08/15/2018 3:43:16.80 - Info: Found Windows Installer version 5.0.17134.1
Wed 08/15/2018 3:43:16.80 - Info: Found Windows Script Host version 5.812.10240.16384
Wed 08/15/2018 3:43:16.80 - Info: Found Internet Explorer version 9.11.17134.0
Wed 08/15/2018 3:43:16.80 - Info: Found Microsoft Silverlight version 5.1.50907.0
Wed 08/15/2018 3:43:16.80 - Info: Found Remote Desktop Client version 10.0.17134.1
Wed 08/15/2018 3:43:16.80 - Info: Found Microsoft .NET Framework 3.5 version 3.5.30729.4926
Wed 08/15/2018 3:43:16.82 - Info: Found Windows PowerShell version 2.0
Wed 08/15/2018 3:43:16.82 - Info: Found Microsoft .NET Framework 4 version 4.7.03056 (release: 461808)
Wed 08/15/2018 3:43:16.82 - Info: Found Windows Management Framework version 5.1.17134.1
Wed 08/15/2018 3:43:16.82 - Info: Found Windows Defender definitions version 1.263.48.0
Wed 08/15/2018 3:43:16.83 - Info: Medium build date: 08/15/2018
Wed 08/15/2018 3:43:16.85 - Info: Medium supports Microsoft Windows (w100 x64 glb)
Wed 08/15/2018 3:43:16.97 - Info: Disabled screensaver
Wed 08/15/2018 3:43:17.11 - Info: Created temporary power scheme
Wed 08/15/2018 3:43:17.32 - Info: Adjusted power management settings
Wed 08/15/2018 3:43:43.54 - Info: Installed ..\msse\x64-glb\mpam-fex64.exe
Wed 08/15/2018 3:43:43.90 - Info: Starting service 'Windows Update' (wuauserv)
Wed 08/15/2018 3:43:43.96 - Info: Waiting for service 'wuauserv' to reach state 'Running' (timeout: 60s)
Wed 08/15/2018 3:43:43.96 - Info: Service 'wuauserv' reached state 'Running'
Wed 08/15/2018 3:43:43.94 - Info: Started service 'Windows Update' (wuauserv)
Wed 08/15/2018 3:45:13.57 - Info: Listed ids of missing updates
Wed 08/15/2018 3:45:13.95 - Info: Listed ids of installed updates
Wed 08/15/2018 3:45:14.07 - Info: Skipped update kb890830 (Malicious Software Removal Tool) due to matching black list entry
Wed 08/15/2018 3:45:14.61 - Info: Listed update files
Wed 08/15/2018 3:45:14.68 - Info: Stopping service 'Windows Update' (wuauserv)
Wed 08/15/2018 3:45:14.70 - Info: Waiting for service 'wuauserv' to reach state 'Stopped' (timeout: 180s)
Wed 08/15/2018 3:45:14.70 - Info: Service 'wuauserv' reached state 'Stopped'
Wed 08/15/2018 3:45:14.70 - Info: Stopped service 'Windows Update' (wuauserv)
Wed 08/15/2018 3:45:33.94 - Info: Installed ..\w100-x64\glb\windows10.0-kb4338853-x64_80cfbdddcd6b20f1230efdf19ce7eac1400e55e9.msu
Wed 08/15/2018 3:52:42.03 - Info: Installed ..\w100-x64\glb\windows10.0-kb4338819-x64_ce89143875d5e85c50ffc6eb8afee157e49cf170.cab
Wed 08/15/2018 3:52:42.60 - Info: Skipped inapplicable ..\w100-x64\glb\windows10.0-kb4338832-x64_a48e4a9660b640331a3658b769eeab0cc74840e4.cab
Wed 08/15/2018 3:52:43.02 - Info: Skipped inapplicable ..\w100-x64\glb\windows10.0-kb4338832-x64_e5dcc6b2af88c3c5bf91ecc497a89dbc51ae6bd1.cab
Wed 08/15/2018 3:52:43.46 - Info: Skipped inapplicable ..\w100-x64\glb\windows10.0-kb4338832-x64_faba11f6a17fe5de6c66c0bc495832d238e1b583.cab
Wed 08/15/2018 3:52:43.88 - Info: Skipped inapplicable ..\w100-x64\glb\windows10.0-kb4338832-x64_1a80d08a0e604805ff03553cbeb19cc7198d09ed.cab
Wed 08/15/2018 3:53:08.91 - Info: Installed ..\w100-x64\glb\windows10.0-kb4338832-x64_60e8f4c0b94ac97a599f3acc4eddaf3abaa057f7.cab
Wed 08/15/2018 3:53:08.94 - Info: Installed 7 updates
Wed 08/15/2018 3:53:08.98 - Info: Restored screensaver setting
Wed 08/15/2018 3:53:09.01 - Info: Activated previous power scheme
Wed 08/15/2018 3:53:09.07 - Info: Deleted temporary power scheme
Wed 08/15/2018 3:53:08.96 - Info: Installation successful
Wed 08/15/2018 3:53:09.10 - Info: Ending WSUS Offline Update
Instead I still see the ones from July in the log.
I begin to lose my trust in WOU as it doesn't work since May...
If I find a bit time I will write my own powershell script to query the MS Update catalog directly for download links and to download the monthly released updates automatically - probably not so difficult - this should be the more reliable way compared to wsusscn2.cab.
@boco: I don't run WSUS download on the target machine - ISO creation happens on server 2016 (Version 14393 = v1607) - but this machine is fully patched - and later on I mount this iso to the Target machine from where I grabbed the logs.