Cache custom fields on instance prior to calling create()/update()

netbox/extras/models/customfields.py

@@ -17,11 +17,14 @@ from extras.utils import FeatureQuery
 #
 
 class CustomFieldModel(models.Model):
-    _cf = None
 
     class Meta:
         abstract = True
 
+    def __init__(self, *args, custom_fields=None, **kwargs):
+        self._cf = custom_fields
+        super().__init__(*args, **kwargs)
+
     def cache_custom_fields(self):
         """
         Cache all custom field values for this instance