diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index e2a0356ef..49e9e23b8 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -1732,7 +1732,7 @@ class PostDocumentSerializer(serializers.Serializer):
         # Normalize single values to a list
         if isinstance(custom_fields, int):
             custom_fields = [custom_fields]
-        elif isinstance(custom_fields, dict):
+        if isinstance(custom_fields, dict):
             custom_field_serializer = CustomFieldInstanceSerializer()
             normalized = {}
             for field_id, value in custom_fields.items():