Checkov's SoftFail not documented, working, and ignored by MSDO

I've got "SoftFail": true in the MSDO config/.gdnconfig for my pipeline/repo,

and this does influence the commandline MSDO generates:

/home/vsts/work/_msdo/packages/nuget/Microsoft.Guardian.CheckovRedist_linux_amd64.3.2.497/tools/dist/checkov --directory /home/vsts/work/1/s/vmss --output sarif --quiet --soft-fail --enable-secret-scan-all-files --output-file-path /home/vsts/work/1/s/.gdn/.r/checkov/001/checkov.sarif

Checkov finds some errors, but returns 0 as instructed by soft fail being enabled.

    Tool run time: 11.7852427 seconds
    ------------------------------------------------------------------------------
    Checkov completed with exit code 0
    ------------------------------------------------------------------------------

The problem is that MSDO breaks my build anyway, because it's scanning for errors, and seems be be ignoring exit codes?

##[error]BreakException: Guardian detected one or more breaking results.

##[error]MSDO CLI exited with an error exit code: 8

Could MSDO be so kind as to respect the exit codes that I've carefully configured for this tool?