laravel backpack repeatable type not working in backpack version 4.1

Question

I want to clone same fields. SO, I am trying to using repeatable type but when I click on add button then no action is performed.

backpack version : 4.1

CRUD::addField([ // Extra Features
            'name'      => 'clergy_discription',
            'label'     => 'Extra Features',
            'type'      => 'repeatable',
            'subfields' => [
                [
                    'name'    => 'feature',
                    'wrapper' => [
                        'class' => 'col-md-3',
                    ],
                ],
                [
                    'name'    => 'quantity',
                    'type'    => 'number',
                    'wrapper' => [
                        'class' => 'col-md-3',
                    ],
                ],
            ],
        ]);