Just did the following in PowerShell:
Click image for larger version. 

Name:	dism-issue-16199.PNG 
Views:	9 
Size:	19.7 KB 
ID:	137001
Sure enough, it's our old familiar error causes as this snippet from cbs.log shows:
Checking System Update Readiness.
(p) CBS MUM Corrupt Microsoft-Windows-TestRoot-and-FlightSigning-Package~31bf3856ad364e35~amd64~~10.0.16199.1000
(p) CBS MUM Corrupt Microsoft-Windows-TestRoot-and-FlightSigning-WOW64-Package~31bf3856ad364e35~amd64~~10.0.16199.1000

Here we go again!
--Ed--