list-add doesn't work for nested list of child attribute

/profile=full/subsystem=elytron/dir-context=dir2:add(url="ldap://test")

/profile=full/subsystem=elytron/ldap-realm=foobar2:add(dir-context=dir2,identity-mapping={rdn-identifier=test})
{
    "outcome" => "success",
    "result" => undefined,
    "server-groups" => {"main-server-group" => {"host" => {"master" => {"server-one" => {"response" => {
        "outcome" => "success",
        "response-headers" => {"process-state" => "reload-required"}
    }}}}}}
}

/profile=full/subsystem=elytron/ldap-realm=foobar2:list-add(name=identity-mapping.new-identity-attributes,value={name=key2,value=["val1","val2"]})
{
    "outcome" => "failed",
    "result" => undefined,
    "server-groups" => undefined,
    "rolled-back" => true
}