I have this methods in class:

public function getOffServers(){
		$off = $this->Children()->filter('Official', 1);
		Debug::show($off);
		return $off;
		}
	public function getNotOffServers(){
		$noff = $this->Children()->filter('Official', 0);
		Debug::show($noff);
		return $noff;
		}
	public function getServers(){
		$s = $this->Children();
		Debug::show($s);
		return $s;
		}

'getOffServers' - i am calling this one first in template, this method works ok but if call "getNotOffServers" i get emply list and when i am calling 'getServers' - i have the same list as 'getOffServers' (not all children), if i am using in template "<% loop children %>" after 'getOffServers' i have just part of chilren (the list is the same as for 'getOffServers' ), do you have ideas ?

Try cloning the DataList to a new variable before adding filters.

$off = $this->Children();

return $off->filter('Official', 1);

Thanks for reply but it doent help(
Output is the same.

I have found solution but it look not so great, i have used this code-

public function getOffServers(){
		$output = new ArrayList();
		$createdOptionsArrayData = false;
		$children = $this->Children();
		foreach ($children as $server) {
			if ($server->Official == '1'){
				$output->push(new ArrayData(array(
				'Title' => $server->Title
				)));
			}
		}
		//Debug::Show($output);
		return $output;
		}

Have you tried perhaps:

<% loop Children.Exclude('Official', 0) %>
   <!-- Loop official servers -->
<% end_loop %>

<% loop Children.Exclude('Official', 1) %>
   <!-- Loop not official servers -->
<% end_loop %>

Thanks, i will try next time.