diff --git a/app/components/pipeline/workflow/event-rail/component.js b/app/components/pipeline/workflow/event-rail/component.js
index 474fb99a4..78a1a88a1 100644
--- a/app/components/pipeline/workflow/event-rail/component.js
+++ b/app/components/pipeline/workflow/event-rail/component.js
@@ -76,7 +76,7 @@ export default class PipelineWorkflowEventRailComponent extends Component {
     const pipelineId = this.args.pipeline.id;
 
     if (this.isPR) {
-      if (this.prNums.length === 0) {
+      if (!this.prNums || this.prNums.length === 0) {
         return [];
       }