finite.yml override issue

[umpirsky]

I have custom core bundle in my Sylius app, and have src/Umpirsky/Bundle/CoreBundle/Resources/config/finite.yml file where I override:

finite_finite:
    sylius_order_shipping:
...

The problem is that sylius_payment callbacks are not loaded at all for some reason. And when I put:

    sylius_payment:
        callbacks:
            after:
                sylius_update_order:
                    on:   'complete'
                    do:   [@sylius.callback.order_payment, 'updateOrderOnPayment']
                    args: ['object']

here it gets loaded twice, once under sylius_update_order key in array loader and once under 0 key. 😖 So its called twice.

Am I doing something wrong or this is a bug in Finite?