I'm using HLK Studio version 1809 on a Windows Server 2016 machine with a Windows Server 2019 client. I'm running the Windows Filtering Platform test on our WFP callout driver, and it's failing at the point where it installs the Sparta MiniPort interfaces. The primary interface is installed and configured correctly, and the DevCon command to create the secondary interface succeeds according to its output, but no secondary interface gets created.
I saw a post in the old Windows HLK forum about this very problem and it suggested updating the client fully via Windows Update to pick up the bug fix. I have done this with my Windows Server 2019 system, but the problem persists. I'm going to try a higher version of HLK Studio to see if that fixes the problem, but I wanted to post here at the same time in case someone already knows the answer to this problem.