UnicodeDecodeError - Django Upload file

I'm using Django Rest Framework, and with a simple form on the frontend I upload some data, and attachments to a model in Django.

I store the files at AWS S3, and I'm using Django S3 Storage.

When I upload a file I get an UnicodeDecodeError as follows. (See bottom for trace)

My file model

class JourAttachment(models.Model):
    jourreport = models.ForeignKey(JourReport,related_name="jourattachments", on_delete=models.CASCADE)
    file = models.FileField(null=False)

View

class JourReportListView(APIView):
    serializer_class = JourReportListSerializer
    permission_classes = (IsAuthenticated, )
    parser_classes = (MultiPartParser,)
    

    def post(self,request,*args, **kwargs):
        
        user_making_request = request.user
        if not user_is_admin(user_making_request):
            return UserNotAdminResponse()

        attachments = request.FILES.getlist('attachment', None)
        
        serializer = JourReportCreateUpdateSerializer(data=request.data,partial=True,context={'attachments': attachments})
        valid = serializer.is_valid(raise_exception=True)
        if valid:
            report = serializer.save()
            
            status_code = status.HTTP_201_CREATED
 
            #send_mail_with_jourreport(report)
            return SuccessfulResponse(data=request.data, message="Jour report successfully registered!" ,status_code=status_code)
    
        return ErrorResponse()

Serializer

class JourReportCreateUpdateSerializer(serializers.ModelSerializer):
    class Meta:
        model = JourReport
        fields = ('apartment_number', 'address', 'tenant_name','tenant_phone', 'debit_tenant','worker','total_hours', 'additional_workers','defect_description','actions_made','actions_to_be_made')

    

    def create(self, validated_data):
        users = []
        attachments = self.context['attachments']
        if "additional_workers" in validated_data:
            users = [w.id for w in validated_data["additional_workers"]]
            del validated_data["additional_workers"]
        
        report = JourReport.objects.create(**validated_data)
        
        for a in attachments:
            
            JourAttachment.objects.create(file=a,jourreport=report) # Add attachments to instance

        if(len(users) > 0):
            report.additional_workers.add(*users)

        return report

The model is correctly added and all files are stored, but either way I get an 500 response with UnicodeDecodeError Trace

Traceback (most recent call last):
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/django/core/handlers/base.py", line 145, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/django/core/handlers/base.py", line 143, in _get_response
    response = response.render()
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/django/template/response.py", line 105, in render
    self.content = self.rendered_content
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/rest_framework/response.py", line 70, in rendered_content
    ret = renderer.render(self.data, accepted_media_type, context)
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/rest_framework/renderers.py", line 100, in render
    ret = json.dumps(
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/rest_framework/utils/json.py", line 25, in dumps
    return json.dumps(*args, **kwargs)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/__init__.py", line 234, in dumps
    return cls(
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/Users/jakobkarlstrand/Documents/Programming/weknowit/HaningeBostader/backend/venv/lib/python3.9/site-packages/rest_framework/utils/encoders.py", line 50, in default
    return obj.decode()
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa2 in position 50: invalid start byte

I also have a custom S3 storage handler:

class CustomS3Storage(S3Storage,ABC):

    def _save(self, name, content):
        """
        We create a clone of the content file as when this is passed to boto3 it wrongly closes
        the file upon upload where as the storage backend expects it to still be open
        """
        # Seek our content back to the start
        content.seek(0, os.SEEK_SET)

        # Create a temporary file that will write to disk after a specified size
        content_autoclose = self.new_temporary_file()

        # Write our original content into our copy that will be closed by boto3
        
        content_autoclose.write(content.read().strip())
        content_autoclose.file = content.file


        # Upload the object which will auto close the content_autoclose instance
        result = super()._save(strip_non_ascii(name), content_autoclose)

        # Cleanup if this is fixed upstream our duplicate should always close
        if not content_autoclose.closed:
            content_autoclose.close()
        

        return result

return SuccessfulResponse(data=request.data,message="Jour report successfully registered!" ,status_code=status_code)