diff --git a/resources/frontend_client/app/query_builder/filters/FilterPopover.react.js b/resources/frontend_client/app/query_builder/filters/FilterPopover.react.js
index de3ef7073a44c36562068600ec2e5f456e97b880..5541dde917687ed45a68067d99cb62f7ea11a21b 100644
--- a/resources/frontend_client/app/query_builder/filters/FilterPopover.react.js
+++ b/resources/frontend_client/app/query_builder/filters/FilterPopover.react.js
@@ -89,7 +89,7 @@ export default class FilterPopover extends Component {
                 if (operator.defaults && operator.defaults[i] !== undefined) {
                     filter.push(operator.defaults[i]);
                 } else {
-                    filter.push();
+                    filter.push(undefined);
                 }
             }
             if (oldOperator) {