I’ve recently been struggling to resolve an update issue whereby every cumulative update from February 2019 would download, install, reboot and then revert upon hitting the 95% complete stage.
After spending hours and hours looking at logs, we raised a support call with Microsoft. To cut a long story short, he explained that the issue was that the system apps had been removed or renamed which he highlighted in the CBS log.
At the time of building our image, we wanted to remove builtin apps like ‘Mixed Reality Portal’ but because they werent a normal appx package we had to remove the system app folder to disable the app.

C:\Windows\SystemApps
By renaming the folder ‘Microsoft.Windows.HolographicFirstRun_cw5n1h2txyewy’ it allowed the app to be disabled.
When looking at the CBS log it states that some or all of the packages needs re-installing for the update to continue.

Upon copying over the systemapps folder contents or renaming them back their original names the update succeeded.