anti affinity hyper-v 2019

Hello,
I setup a new Hyper-v 2019 cluster 2 nodes and build anti affinity rules but it's not working. Is there any special requirements or limitations ?
VM stay on the same node.
I use microsoft documentation :
$AntiAffinity = New-Object System.Collections.Specialized.StringCollection
$AntiAffinity.Add("DC")
(Get-ClusterGroup -Name "DC1").AntiAffinityClassNames = $AntiAffinity
(Get-ClusterGroup -Name "DC2").AntiAffinityClassNames = $AntiAffinity
I can see both DC1 and DC2 with DC anti affinity group DC with the following command
Get-ClusterGroup | fl AntiAffinityClassNames