diff --git a/packages/netlify-cms-core/src/components/Editor/EditorControlPane/Widget.js b/packages/netlify-cms-core/src/components/Editor/EditorControlPane/Widget.js
index e7963e98..c05de96d 100644
--- a/packages/netlify-cms-core/src/components/Editor/EditorControlPane/Widget.js
+++ b/packages/netlify-cms-core/src/components/Editor/EditorControlPane/Widget.js
@@ -194,7 +194,10 @@ export default class Widget extends Component {
    */
   onChangeObject = (fieldName, newValue, newMetadata) => {
     const newObjectValue = this.getObjectValue().set(fieldName, newValue);
-    return this.props.onChange(newObjectValue, { [this.props.field.get('name')]: newMetadata });
+    return this.props.onChange(
+      newObjectValue,
+      newMetadata && { [this.props.field.get('name')]: newMetadata },
+    );
   };
 
   render() {