removeaccessrule with powershell on AD OrganizationalUnit not working

Question

I have a delegated permission on an OU that I would like to delete.

$SB = "OU=Name of OU,DC=Name,DC=of,DC=Domain"
$ADUC=Get-ADOrganizationalUnit $SB
$OUACL=Get-ACL AD:\$ADN

I can get the ACL-Entry I would like to delete with following script:

foreach ($access in $OUACL.access){
    foreach ($Value in $access.ObjectType){
        if ($Value -like "bf967a0a-0de6-11d0-a285-00aa003049e2"){
            foreach ($Inherit in $Access.IsInherited){
                if ($Inherit -like "False"){
                    $Removeme = $Access
                    #$OUACL.RemoveAccessRule($access) | Out-null
                }
            }
        }
    }
}

the Variable is correctly filled with the Entry I am looking to remove:

ActiveDirectoryRights : ExtendedRight
InheritanceType       : Descendents
ObjectType            : bf967a0a-0de6-11d0-a285-00aa003049e2
InheritedObjectType   : 00000000-0000-0000-0000-000000000000
ObjectFlags           : ObjectAceTypePresent
AccessControlType     : Allow
IdentityReference     : DOMAIN\GroupName
IsInherited           : False
InheritanceFlags      : ContainerInherit
PropagationFlags      : InheritOnly

But If I use $OUACL.RemoveAccessRule($access) I get the return code "False" and the Entry is still within the ACL.

what am I missing?

I tried to remove the Accessrule from ACS and then save it. (the set-acl part is missing, because removefromAccessRule is not working)