Just a heads up but according to a windows update error list I found the error code we've been seeing is this:
0x80240020 WU_E_NO_INTERACTIVE_USER Operation did not complete because there is no logged-on interactive user.
I found the list here:
https://support.microsoft.com/en-us/kb/938205
I do not know why this error is happening or how to solve it, but I thought I would pass along the info I found. It no longer affects me as I'm back to running windows 10 via the media creation tool.