The following works (but I have an additionnal column for the hidden form.id
{% for form in data_formset %}
<tr>
<td>{{ form.id }}</td>
<td>{{ form.DELETE }}</td>
<td>{{ form.champ1 }}</td>
<td>{{ form.champ2}}</td>
</tr>
{% endfor %}
While the following does not work, the form will raise a validation error (form.id is required)…
{% for form in data_formset %}
<tr>
{{ form.id }}
<td>{{ form.DELETE }}</td>
<td>{{ form.champ1 }}</td>
<td>{{ form.champ2}}</td>
</tr>
{% endfor %}