diff --git a/test/unit/path-effects.html b/test/unit/path-effects.html
index 93b8401898..feebb9c901 100644
--- a/test/unit/path-effects.html
+++ b/test/unit/path-effects.html
@@ -1218,6 +1218,7 @@
 
   // TODO(kschaaf): address code in `getArgValue` that looks in changedProps
   // when `undefined` for splices, which breaks this test (latent issue)
+  // https://github.com/Polymer/polymer/issues/5479
   test.skip('reentry after prop goes back to undefined', function() {
     let el = document.createElement('x-reentry-undefined');
     document.body.appendChild(el);
@@ -1231,6 +1232,7 @@
 
   // TODO(kschaaf): address code in `getArgValue` that looks in changedProps
   // when `undefined` for splices, which breaks this test (latent issue)
+  // https://github.com/Polymer/polymer/issues/5479
   test.skip('reentry after path goes back to undefined', function() {
     let el = document.createElement('x-reentry-undefined-path');
     document.body.appendChild(el);