Import-DCConditionalAccessPolicyDesign delete existing not working

[kathodion]

Import-DCConditionalAccessPolicyDesign @parameters
$Parameters = @{
FilePath = 'C:\Temp\Conditional Access.json'
SkipReportOnlyMode = $false
DeleteAllExistingPolicies = $false
}

does not remove the existing CA rules. It just adds the new ones