Django inline formset not valid on update - django

Question

My create method works perfectly, but the update does not. It returns one error for each inline as an empty list []
forms.py
StructureFormset = inlineformset_factory(Plan, Structure,
fields = (
'material_type',
'weight',
'thickness',
'provider'
),
extra=0,
can_delete=True
)
TestFormset = inlineformset_factory(Plan, Test,
fields=(
'essay',
'critic',
'spec'
),
extra = 0,
can_delete=True
)
class PlanForm(ModelForm):
class Meta:
model = Plan
fields = (
'format',
'pc',
'revission',
'rev_date',
'client',
'product',
'gp_code',
'code',
'observation',
'continuation',
'dispatch_conditions',
'elaborator',
'reviewer'
)
localized_fields=('rev_date',)
views.py
def editPlan(request, pk):
plan = Plan.objects.get(id = pk)
form = PlanForm(instance = plan)
sformset = StructureFormset(instance=plan)
tformset = TestFormset(instance=plan)
context = {
'form': form,
'sformset': sformset,
'tformset': tformset
}
if request.method == 'POST':
print('----------------------------request----------------------------')
print(request.POST)
form = PlanForm(request.POST, instance = plan)
sformset = StructureFormset(request.POST, instance=plan, prefix='structure')
tformset = TestFormset(request.POST, instance=plan, prefix='test')
if form.is_valid() and sformset.is_valid() and tformset.is_valid():
print('-----------------------is valid-----------------------')
form.save()
instances = sformset.save(commit=False)
for instance in instances:
sformset.save_m2m()
instance.save()
tformset.save()
return redirect('/plans/')
else:#printing errors
print('-----------------------is not valid-----------------------')
print(sformset.total_error_count())
print(sformset.errors)
print(tformset.total_error_count())
print(tformset.errors)
return render(request, 'home/plan_forms.html', context)
template.html
{{ tformset.management_form }}
<table>
<thead>
<tr>
<th>Essay</th>
<th>
<abb title="Critical Variable">Crit.</abb>
</th>
<th>Spec</th>
{% if tformset.instance.pk %}
<th class="text-center px-1 col-1 pb-2">
<i class="material-icons">delete</i>
</th>
{% endif %}
</tr>
</thead>
<tbody id="tform_set">
<!--Test form goes here-->
{% if tformset %}
{% for tt in tformset %}
{% for hidden in tt.hidden_fields %}
{{ hidden }}
{% endfor %}
<tr>
<td>
{{ tt.essay }}
</td>
<td class="px-1 col-1 text-center justify-content-center">
{{ tt.critic }}
</td>
<td>
{{ tt.spec }}
</td>
<td>
{% if tt.instance.pk %}{{ tt.DELETE }}{% endif %}
</td>
</tr>
{% endfor %}
{% endif %}
</tbody>
<tbody id="tempty_form" style="display:none !important;">
<tr>
<td>
{{ tformset.empty_form.essay }}
</td>
<td>
{{ tformset.empty_form.critic }}
</td>
<td>
{{ tformset.empty_form.spec }}
</td>
</tr>
</tbody>
</table>
{{ sformset.management_form }}
<table>
<thead>
<tr>
<th>Material</th>
<th>Weight (g/m²)</th>
<th>Thickness (μ)</th>
<th>Provider</th>
{% if sformset.instance.pk %}
<th class="text-center col-1 px-1 pb-2">
<i class="material-icons">delete</i>
</th>
{% endif %}
</tr>
</thead>
<tbody id="sform_set">
<!--Structure form goes here-->
{% if sformset %}
{% for ss in sformset %}
{% for hidden in ss.hidden_fields %}
{{ hidden }}
{% endfor %}
<tr>
<td>
{{ ss.material_type }}
</td>
<td>
{{ ss.weight }}
</td>
<td>
{{ ss.thickness }}
</td>
<td>
{{ ss.provider }}
</td>
<td>
{% if ss.instance.pk %}{{ ss.DELETE }}{% endif %}
</td>
</tr>
{% endfor %}
{% endif %}
</tbody>
<tbody id="sempty_form" style="display:none !important;">
<tr>
<td>
{{ sformset.empty_form.material_type }}
</td>
<td>
{{ sformset.empty_form.weight }}
</td>
<td>
{{ sformset.empty_form.thickness }}
</td>
<td>
{{ sformset.empty_form.provider }}
</div>
</td>
</tr>
</tbody>
</table>
This is what i get from the prints;
notice the:
`
1
[]
1
[]
` bellow the `is not valid`
[![Print Output](https://i.stack.imgur.com/whRc0.png)](https://i.stack.imgur.com/whRc0.png)