serialization - Django REST Framework, PUT/POST serializer data disappearing -

i having trouble part of data disappearing when try update or post new instance.

with data this

data = {         'item': 'product',          'station': 'workbench',          'ingredients':[             {'item': 'ing1', 'amount': 2},             {'item': 'ing2', 'amount':1}          ]         } 

i have serializer nested serializer get_or_creates ingredients needed.

class ingredientserializer(serializers.modelserializer):      class meta:         model = ingredient         fields = ('item', 'amount')   class writeablerecipeserializer(serializers.modelserializer):     item = serializers.primarykeyrelatedfield(queryset=item.objects.all())     ingredients = ingredientserializer(many=true)     station = serializers.primarykeyrelatedfield(queryset=item.objects.all())      def create(self, validated_data):         logger.info(validated_data)         ingredient_data = validated_data.pop('ingredients')         recipe = recipe.objects.create(**validated_data)          ingredient in ingredient_data:             ingredient_item = item.objects.get(name=ingredient['item'])             amount = ingredient['amount']             ingredient, created = ingredient.objects.get_or_create(item=ingredient_item, amount=amount                                    )             recipe.ingredients.add(ingredient)          return recipe      def update(self, instance, validated_data):         logger.info(validated_data)         ingredient_data = validated_data.pop('ingredients')         instance.item = validated_data.get('item', instance.item)         instance.station = validated_data.get('station', instance.station)          ingredient in ingredient_data:             ingredient_item = item.objects.get(name=ingredient['item'])             amount = ingredient['amount']             ingredient, created = ingredient.objects.get_or_create(item=ingredient_item, amount=amount)             logger.info('itering')             instance.ingredients.add(ingredient)          return instance      class meta:         model = recipe         fields = ('item', 'amount', 'ingredients', 'station') 

the data validates , response code 200, both response data , validated_data shown logger in create , update methods return this:

    data = {         'item': 'product',          'station': 'workbench',          'ingredients':[]         } 

the ingredients data going awol somewhere. have tried making ingredient serializer generic serializer overriding writeablerecipeserializer's validation return attrs problem persists.

edit models:

class ingredient(models.model):     item = models.foreignkey(item, on_delete=models.cascade)     amount = models.integerfield()      def __str__(self):         return self.item.name + '(' + str(self.amount) + ')'  class recipe(models.model):     item = models.onetoonefield(item, related_name='recipe', on_delete=models.cascade)     amount = models.integerfield(default=1)     ingredients = models.manytomanyfield(ingredient)     station = models.foreignkey(item, on_delete=models.cascade, related_name='as_station')      def __str__(self):         return 'recipe: ' + str(self.item)