Gitlab shared windows runners - cannot install dotnet core

This has been working fine for the past few weeks that we’ve been using shared windows runners. It even worked as recently as 3 hours ago. But now, this same powershell command on windows runners is failing. As a freemium user, spending 30 build minutes to fail is getting expensive so I’m no eager to keep hitting retry if this is a known issue.

$ powershell Install-WindowsFeature Net-Framework-Core
Success Restart Needed Exit Code      Feature Result                               
------- -------------- ---------      --------------                               
False   No             Failed         {}                                           
Install-WindowsFeature : The request to add or remove features on the specified server failed.
Installation of one or more roles, role services, or features failed. Error: 0x800f0950
At line:1 char:1
+ Install-WindowsFeature Net-Framework-Core
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (@{Vhd=; Credent...Name=localhost}:PSObject) [Install-WindowsFeature], 
    Exception
    + FullyQualifiedErrorId : DISMAPI_Error__Failed_To_Enable_Updates,Microsoft.Windows.ServerManager.Commands.AddWind 
   owsFeatureCommand

Google results are few, and they all assume local/admin/physical possession of the box, not ephemeral build slaves that I have no control over.

Relevant yaml markup:

.shared_windows_runners:
  tags:
  - shared-windows
  - windows
  - windows-1809

publish:
  extends:
    - .shared_windows_runners
  stage: publish
  script:
    - powershell Install-WindowsFeature Net-Framework-Core

We finally got a good build to process. No acknowledgement of any issues by gitlab, though.