Making MB Group work with MB Blocks

I read in another support ticket that MB Groups gives you the possibility to add repeater fields. I installed MB Group and also integrated it with MB Blocks, example code shown below:

// Block fields.
        'fields'          => [
                'type' => 'group',
                'id'   => 'faq_items',
                'name' => 'FAQ Items',
                'fields' => array(
                    array(
                        'name' => 'Question Title',
                        'id'   => 'question_title',
                        'type' => 'text',
                    ),
                    array(
                        'name' => 'Question Answer',
                        'id'   => 'question_answer',
                        'type' => 'text',
                    ),
                ),
            ],

This is added to the Gutenberg Block, however, it is not a repeatable list (group). Any ideas on what I might be missing, please?