STATUSIssue fixed in version 6.0 LTS
WORKAROUNDThe API can be used to perform the same task. A basic template is provided below. This will need to be edited to suit your purposes.
Start with GETting a directory user group, which will be used as a template.
$dug = Get-SafeguardUserGroup -GroupToGet {ID or name}
Edit the directory properties with the new group's DirectoryID, DomainName, DistinguishedName values. Probably can omit / remove entirely the ObjectGuid and ObjectSid properties. Also set the group's name.
$dug.DirectoryProperties.DirectoryID= {directoryId}
$dug.DirectoryProperties.DomainName = {DN}
$dug.DirectoryProperties.DistinguishedName = {Distinguished name}
$dug.Name = {new group's name}
Then POST to create a new group
Invoke-SafeguardMethod core post "UserGroups" -body $dug