I installed KB 2910552 back on the 8th of this month, and that appeared to speed up the "Downloading [osname].wim" task that's part of the Task Sequence.
It sped it up to about 1% every 1 second.
But now it's back to 1% about every 15 seconds, greatly increasing the time it takes to complete an OS deployment.
Why is this? I'm not seeing any other updates installed since then that would affect it.
The hotfix is still showing to be installed
I'm wondering if since the the OS image .wim file got updated on the 19th, and even updated to the DP, if I need to uninstall then reinstall the hotfix?