Error arg 1 $view null given - when displaying a Symfony form in pieces via form_start, form_widget, form_row, etc

When I use {{ form(group_mapping_form) }} the form renders, but when I try to access dynamically generated form field names with {{ form_widget(attribute(group_mapping_form, 'use_code_' ~ group.id)) }} I get the following error:

Uncaught PHP Exception TypeError: "Symfony\Component\Form\FormRenderer::searchAndRenderBlock():
Argument #1 ($view) must be of type Symfony\Component\Form\FormView, null given

PHP Controller (Partial Code)

    $form = $this->createFormBuilder();

    $groups = json_decode($response->getContent());
    foreach ($groups as $group) {
      $form->add('use_code_' . $group->id, ChoiceType::class, [
        'choices' => [
          'Select One' => [
            'none' => '',
            'A' => 'A',
            'B' => 'B',
            'C' => 'C',
            'D' => 'D',
            'E' => 'E',
            'F' => 'F',
            'G' => 'G',
            'H' => 'H',
            'I' => 'I',
            'J' => 'J',
          ],
        ],
      ]);
    }

    $form->add('submit', SubmitType::class, ['label' => 'Submit']);
    $form = $form->getForm();

    return $this->render('group_mapping_form.html.twig', [
      'group_mapping_form' => $form->createView(),
      'groups' => $groups ?: '',
    ]);

Twig File

{% extends "base.html.twig" %}

{% block stylesheets %}
  {{ parent() }}
  <link href="{{ asset('css/table.css') }}" rel="stylesheet"/>
{% endblock %}

{% block body %}
  {% if group_mapping_form is not empty %}
    {{ form_start(group_mapping_form) }}
    <table class="styled-table">
      <thead>
      <tr>
        <th>Group Name</th>
        <th>Entity Use Code</th>
      </tr>
      </thead>
      <tbody>
      {% if groups is not empty %}
        {% for group in groups %}
          <tr>
            <td>
              <div class="cell-border">{{ group.name }}</div>
            </td>
            <td>
              <div class="cell-border">{{ form_widget(attribute(group_mapping_form, 'use_code_' ~ group.id)) }}</div>
            </td>
          </tr>
        {% endfor %}
      {% else %}
        <tr>
          <td>No Records Found!</td>
        </tr>
      {% endif %}
      </tbody>
    </table>

    {{ form_widget(form.submit) }}
    {{ form_end(group_mapping_form) }}

  {% endif %}
{% endblock %}

I just needed to change {{ form_widget(form.submit) }} to {{ form_widget(group_mapping_form.submit) }} and that fixed it.