Spree Issues config.action_view.raise_on_missing_translations

I'm working on a Rails Spree 4.1 app.
I enabled raising exception on missing translations via the option config.action_view.raise_on_missing_translations in config/environment/development.rb.
It's nice to know I a tranlsation is missing.

This was working fine, until I included the spree_mollie_gateway.

I couldn't boot the rails application anymore. It constantly raised:

gems/i18n-1.8.3/lib/i18n.rb:373:in `handle_exception': translation missing: nl.spree.validation.must_be_int (I18n::MissingTranslationData)

The woraround I now use is this: (config/development.rb)
Just enable it after the GEM is loaded

# Raises error for missing translations.
  config.action_view.raise_on_missing_translations = false
  Rails.application.config.to_prepare do
    ActionView::Base.raise_on_missing_translations = true
  end