FR creation error 2022.04.15

 - - [15/Apr/2022:14:26:57 +0000] "GET /api/v2/ HTTP/1.0" 200 4305 "-" "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; AppInsights)"
2022-04-15 14:27:21 ERROR    Could not create Field Report.
Traceback (most recent call last):
  File "/home/ifrc/go-api/api/drf_views.py", line 918, in create
    fieldreport = FieldReport.objects.create(**data)
  File "/usr/local/lib/python3.8/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/modeltranslation/manager.py", line 362, in create
    return super(MultilingualQuerySet, self).create(**kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/models/query.py", line 422, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/ifrc/go-api/api/models.py", line 1404, in save
    return super(FieldReport, self).save(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/django/db/models/base.py", line 743, in save
    self.save_base(using=using, force_insert=force_insert,
  File "/usr/local/lib/python3.8/site-packages/django/db/models/base.py", line 791, in save_base
    post_save.send(
  File "/usr/local/lib/python3.8/site-packages/django/dispatch/dispatcher.py", line 173, in send
    return [
  File "/usr/local/lib/python3.8/site-packages/django/dispatch/dispatcher.py", line 174, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "/usr/local/lib/python3.8/site-packages/reversion/revisions.py", line 328, in _post_save_receiver
    add_to_revision(instance, model_db=using)
  File "/usr/local/lib/python3.8/site-packages/reversion/revisions.py", line 213, in add_to_revision
    _add_to_revision(obj, db, model_db, True)
  File "/usr/local/lib/python3.8/site-packages/reversion/revisions.py", line 189, in _add_to_revision
    serialized_data=serializers.serialize(
  File "/usr/local/lib/python3.8/site-packages/django/core/serializers/__init__.py", line 128, in serialize
    s.serialize(queryset, **options)
  File "/usr/local/lib/python3.8/site-packages/django/core/serializers/base.py", line 107, in serialize
    self.handle_field(obj, field)
  File "/usr/local/lib/python3.8/site-packages/django/core/serializers/python.py", line 50, in handle_field
    self._current[field.name] = self._value_from_field(obj, field)
  File "/usr/local/lib/python3.8/site-packages/django/core/serializers/python.py", line 47, in _value_from_field
    return value if is_protected_type(value) else field.value_to_string(obj)
  File "/usr/local/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1440, in value_to_string
    return '' if val is None else val.isoformat()
AttributeError: 'str' object has no attribute 'isoformat'

==> /home/ifrc/logs/logger.log <==
2022-04-15 14:27:21,070 WARNING Bad Request: /api/v2/create_field_report/