Non-deterministic sort in paginator (Cake/2.5.0)

I’ve implemented sort links using PaginatorHelper::sort() as explained in docs. It works but it only sorts by that column. That means that when the chosen column is not unique CakePHP runs pagination queries that do not have a deterministic order, e.g.:

ORDER BY `Vehicle`.`make` asc LIMIT 20, 20

It’d a very obvious bug to go unnoticed so I’m wondering if I’m doing something wrong. My links are like:

<th><?php echo $this->Paginator->sort('Vehicle.make', __d('foo_manager', 'make')); ?></th>

… and I haven’t added any specific sort code to the controller.