diff --git a/testing/web-platform/meta/ua-client-hints/useragentdata.https.any.js.ini b/testing/web-platform/meta/ua-client-hints/useragentdata.https.any.js.ini
index 78505799c01e..f57232a2795f 100644
--- a/testing/web-platform/meta/ua-client-hints/useragentdata.https.any.js.ini
+++ b/testing/web-platform/meta/ua-client-hints/useragentdata.https.any.js.ini
@@ -2,7 +2,13 @@
   [tests for navigator.userAgentData]
     expected: FAIL
 
+  [test NavigatorUAData.toJSON() output]
+    expected: FAIL
+
 
 [useragentdata.https.any.html]
   [tests for navigator.userAgentData]
     expected: FAIL
+
+  [test NavigatorUAData.toJSON() output]
+    expected: FAIL