This is absolutely nothing new, and the workaround is usually just a small registry tweak so Windows Update pulls from the extended support patches “channel”. Same thing happened with Vista, 7, and 8.

Alternatively there are ways to download from the Windows Update servers using plenty of third party tools. It’s a neccessity if you’re going to streamline patches into your install media to save the post install mess of waiting for it to download and install all the updates that have come out since they first made the install .iso