Problem

Mollie's transport form template (Resources/views/Form/fields.html.twig) renders the parent form's synchronizationSettings field without checking whether it has already been rendered:

{% if (form.parent.synchronizationSettings is defined) %}
    {{ form_widget(form.parent.synchronizationSettings) }}
{% endif %}

Oro's update.html.twig conditionally renders synchronizationSettings as a separate data block when form.synchronizationSettings.count > 0:

{% if (form.synchronizationSettings is defined and form.synchronizationSettings.count) %}
    {% set dataBlocks = dataBlocks|merge([{...
        'data':  [form_widget(form.synchronizationSettings)]   {# render #1 #}
    }]) %}
{% endif %}

Later, form_widget(form) triggers the transport widget block, which calls Mollie's template — rendering the same field a second time. This produces:

Field "synchronizationSettings" has already been rendered, save the result of
previous render call to a variable and output that instead.

This is a latent bug in all Mollie versions — it was masked because the only two synchronization_settings fields (isTwoWaySyncEnabled, syncPriority) are gated by an applicable restriction that filters them out for Mollie integrations, keeping .count at 0 and skipping the data block entirely.

A recent Oro 6.1.x patch release added a logWarnings checkbox without an applicable restriction:

# oro/platform IntegrationBundle/Resources/config/oro/integrations.yml
logWarnings:
    type: Symfony\Component\Form\Extension\Core\Type\CheckboxType
    options:
        label: oro.integration.integration.log_warnings.label
        required: false

This makes .count = 1 for all integration types, including Mollie — triggering the double render.

Oro's own IntegrationBundle/Resources/views/Form/fields.html.twig already guards against this with a .rendered check:

{% if (form.synchronizationSettings is defined and not form.synchronizationSettings.rendered) %}

Reproduction

1. Install OroCommerce 6.1.x (with the logWarnings sync setting present)
2. Install mollie/orocommerce 6.1.0
3. Navigate to Admin → System → Integrations → Manage Integrations
4. Create or edit a Mollie integration
5. Observe the Twig error about synchronizationSettings being rendered twice

Suggested Fix

Add a .rendered check to Mollie's template, matching Oro's own pattern:

-    {% if (form.parent.synchronizationSettings is defined) %}
+    {% if (form.parent.synchronizationSettings is defined and not form.parent.synchronizationSettings.rendered) %}
         {{ form_widget(form.parent.synchronizationSettings) }}
     {% endif %}

Environment

• mollie/orocommerce: 6.1.0 (latent in all versions)
• Surfaces on OroCommerce 6.1.x patch releases that include the logWarnings sync setting