This mixin reloads the full object using the queryset the default mixin removes all the select related, causing issues with serializers that contains data from different entities. That way we use the queryset defined. We should use this update mixin in all places with prefetches, mainly with custom fields. The issue in the original implementation, is that when the object gets saved, and all the prefeetches are dropped So the serializer of the response has to re query everything, and if we have lists to process, it does N+1