Hello @sdemonte , I’ve reached out to contacts at Microsoft for assistance on this item as the root of the problem is with the patch binary hosted in the catalog. Here is the supporting details:
If you manually download this binary and test / validate the sha1, you’ll see the differences between what is documented by Microsoft in the image above and also embedded in the filename:
Q: (base64 decode "KFYM+twQMKtg5A3azTaDFl9AvFg=") as hexadecimal
A: 28560cfadc1030ab60e40ddacd3683165f40bc58
T: 6328.420 ms
I: singular string
Q: sha1 of files "C:\Users\Gus\Downloads\windows10.0-kb5123099-x64_28560cfadc1030ab60e40ddacd3683165f40bc58.msu"
A: 57f2f2a6028a6f11d0fc96a5f6057912ef0ad4d5
T: 6328.349 ms
I: singular string
This is also applicable to fixlet 512309905 - MS26-SEP: Cumulative Update for Windows Server 2016 - Windows Server 2016 - KB5123099 (x64) as they share the same patch binary. More details to follow as they develop.
Thanks, Gus.