Laravel 5 > touch pivot table (Many-to-Many) -

why updated_at field in pivot table not updating giving following setup?

model

class conversation extends model {      public function users()     {        return $this->belongstomany('app\user')->withtimestamps();     } } 

controller

$conversation = conversation::find($id); $conversation->users()->touch(); 

the last line should - far understand whole thing - update pivots table updated_at field, shouldn´t it?

but isn´t. right have manualy via db query.