diff --git a/lib/app/communications/customer.js b/lib/app/communications/customer.js
index 4b5994e..2640c93 100644
--- a/lib/app/communications/customer.js
+++ b/lib/app/communications/customer.js
@@ -543,7 +543,7 @@ class CustomerCommunication {
                                         enabled: item => !item.OptOut && !item.OptOut_BC,
                                         onchanged: function () {
                                             if (typeof option.onChanged === 'function') {
-                                                option.onChanged(This.#gridContact.source.concat(This.#gridWo.source));
+                                                option.onChanged([...This.#gridContact.source, ...This.#gridWo.source]);
                                             }
                                         }
                                     }