The MDT task sequence step "Execute Runbook" was a vital part of our imaging process. Recently we upgrade to SCORCH 2022 and it doesn't seem to work any longer. It seems that since Microsoft changed the API to JSON, even the 8456 version of MDT's "Execute Runbook" stop can't access the API. I can access it using PowerShell like this. I may have to resort to doing it that way. 
$OrchURI = 'http://scorch.contoso.com:81' #Replace 5001 by the WebService port
$RunbookPath = '\Server\ServerOSDRunbook'
$RunbookID = ((Invoke-RestMethod -uri ('{0}/api/Runbooks' -f $OrchURI) -UseDefaultCredentials -AllowUnencryptedAuthentication) |
Select-Object -ExpandProperty value | Where-Object {$_.Path -eq $RunbookPath}).Id
# To Start a job
$body = @{
RunbookId = $RunbookID
Parameters = @(
[pscustomobject]@{Name='OSDAutoPatch';Value='True'}
[pscustomobject]@{Name='OSDADManagedBy';Value='bgates'}
[pscustomobject]@{Name='OSDComputerDescription';Value='Test Server'}
[pscustomobject]@{Name='OSDComputerName';Value='OSDTEST1'}
)
CreatedBy = $null
} | ConvertTo-Json
Invoke-RestMethod -Uri ('{0}/api/Jobs' -f $OrchURI) -Body $body -Method Post -ContentType 'application/json' -UseDefaultCredentials -AllowUnencryptedAuthentication