diff --git a/specification/resources/apps/responses/apps_validate_rollback.yml b/specification/resources/apps/responses/apps_validate_rollback.yml
index ad64e4132..b2074a9f1 100644
--- a/specification/resources/apps/responses/apps_validate_rollback.yml
+++ b/specification/resources/apps/responses/apps_validate_rollback.yml
@@ -27,7 +27,7 @@ content:
           warnings:
             - code: image_source_missing_digest
               components: ["docker-worker"]
-              message: one or more components are missing an image digest and are not guaranteed rollback to the old version
+              message: one or more components are missing an image digest and are not guaranteed rollback to the old version.
       "Invalid rollback":
         value:
           valid: false