by boco » 20.03.2018, 13:56
Usually the Rollup packages are fully cumulative, that means, every new one relaces ALL older ones (currently from Oct. 2017 which was the first).
If now the latest one from March is hidden (or Windows thinks it is hidden), or if it is otherwise inapplicable (that's the case for systems without the QualityCompat key/value), Windows Update will offer the next older one from the chain your system fulfills requirements for.
If the QualityCompat key/value is missing, that is 2017-12 (the last one that did NOT require that value to be present). If the one from March is assumed to be hidden, then it's the next older one from February.
So, the behavior of WU is at least halfway logical, although the reason it offered both in sequence is not. The causes of the behavior is unknown.
You could try to reset WU, that will make it forget anything that was hidden.
1. Stop the Windows Update Service.
2. Delete (or rename) the SoftwareDistribution subdirectory that's inside the WINDOWS directory.
3. Start the Windows Update Service.
Now WU is squeaky-clean and will hopefully act sane, again.
Microsoft update catalog: http://catalog.update.microsoft.com/v7/site/
Windows Install media download: https://support.microsoft.com/en-us/help/15088/windows-create-installation-media