diff --git a/app/assets/javascripts/webhooks/components/form_custom_headers.vue b/app/assets/javascripts/webhooks/components/form_custom_headers.vue
index 4791b69b3f56854b48810610ada7bb62576f8502..df5f06372c7439cf1540cc51b17596db9e88c5a9 100644
--- a/app/assets/javascripts/webhooks/components/form_custom_headers.vue
+++ b/app/assets/javascripts/webhooks/components/form_custom_headers.vue
@@ -49,7 +49,9 @@ export default {
       this.customHeaders.splice(index, 1);
     },
     onUpdate(index, newValues) {
-      this.$set(this.customHeaders, index, newValues);
+      const copy = [...this.customHeaders];
+      copy[index] = newValues;
+      this.customHeaders = copy;
     },
     handleSubmit(e) {
       this.isValidated = true;