Buttons display twice

I have in my code the following buttons

action_promotions_list = [{
    'icon': '',
    'title': 'Activas',
    'payload': '/active_promotions'
}, {
    'icon': '',
    'title': 'Próximas',
    'payload': '/upcoming_promotions'
}, {
    'icon': '',
    'title': 'Regalos',
    'payload': '/gift_promotions'
}, {
    'icon': '',
    'title': 'Promociones generales',
    'payload': '/main_promotions'
}, {
    'icon': '',
    'title': 'Lanzamientos',
    'payload': '/release_promotions'
}, {
    'icon': '',
    'title': 'Formas de pago',
    'payload': '/ask_payment_methods'
}, {
    'icon': '',
    'title': 'Cupones',
    'payload': '/coupons_promotions'
}]

...

dispatcher.utter_message(response='utter_trash', custom={
                'payload': 'productResponse',
                'responses': [response]
            }, buttons=action_promotions_list)

But in the interactive mode display my buttons twice.

There is an explanation why happens here

UPDATED There is a note I have to share: The varialbe action_promotions_list is set in my constants.py

I imported using from import notation.

Thanks