diff --git a/js/src/devtools/automation/cgc-jstests-slow.txt b/js/src/devtools/automation/cgc-jstests-slow.txt
index 814ad338e5fe..21534d4a757f 100644
--- a/js/src/devtools/automation/cgc-jstests-slow.txt
+++ b/js/src/devtools/automation/cgc-jstests-slow.txt
@@ -42,6 +42,7 @@ ecma_5/Object/15.2.3.6-redefinition-1-of-4.js
 ecma_5/Object/15.2.3.6-redefinition-2-of-4.js
 ecma_5/Object/15.2.3.6-redefinition-3-of-4.js
 ecma_5/Object/15.2.3.6-redefinition-4-of-4.js
+ecma_6/extensions/array-isArray-proxy-recursion.js
 ecma_6/String/normalize-generateddata-part0.js
 ecma_6/String/normalize-generateddata-part1-not-listed.js
 ecma_6/String/normalize-generateddata-part1.js