diff --git a/testing/web-platform/meta/MANIFEST.json b/testing/web-platform/meta/MANIFEST.json
index a66385ed9070..95f50de28dda 100644
--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -591142,11 +591142,11 @@
    "manual"
   ],
   "fullscreen/api/element-request-fullscreen-two-elements-manual.html": [
-   "9611c8165663f8e633be20c2e34fb8b04378a44e",
+   "3291664c63ab4880dd844e5f75046d2f93c8f92f",
    "manual"
   ],
   "fullscreen/api/element-request-fullscreen-two-iframes-manual.html": [
-   "99a7672e71c9617f1b73c87d6dcfe694f23563a4",
+   "94b38c0302a5fa32f72dd63c505cf0b73d7e6a73",
    "manual"
   ],
   "fullscreen/api/historical.html": [
diff --git a/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-elements-manual.html b/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-elements-manual.html
index 9611c8165663..3291664c63ab 100644
--- a/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-elements-manual.html
+++ b/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-elements-manual.html
@@ -19,8 +19,11 @@ async_test(t => {
     assert_in_array(document.fullscreenElement, [a, b]);
     order.push(document.fullscreenElement.id);
     if (order.length == 2) {
-      assert_array_equals(order, ['b', 'a'],
-                          'fullscreenElement IDs in fullscreenchange events');
+      // Since fullscreenchange event occurs at animation frame timing we might
+      // have not seen the transition from null -> 'b' but just see the
+      // resulting 'a' transition twice.
+      assert_true(order[0] == 'a' || order[0] == 'b', 'first id seen is a or b');
+      assert_true(order[1] == 'a', 'second id seen is b');
       t.done();
     }
   });
diff --git a/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-iframes-manual.html b/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-iframes-manual.html
index 99a7672e71c9..94b38c0302a5 100644
--- a/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-iframes-manual.html
+++ b/testing/web-platform/tests/fullscreen/api/element-request-fullscreen-two-iframes-manual.html
@@ -21,8 +21,11 @@ async_test(t => {
     assert_in_array(document.fullscreenElement, [a, b]);
     order.push(document.fullscreenElement.id);
     if (order.length == 2) {
-      assert_array_equals(order, ['b', 'a'],
-                          'fullscreenElement IDs in fullscreenchange events');
+      // Since fullscreenchange event occurs at animation frame timing we might
+      // have not seen the transition from null -> 'b' but just see the
+      // resulting 'a' transition twice.
+      assert_true(order[0] == 'a' || order[0] == 'b', 'first id seen is a or b');
+      assert_true(order[1] == 'a', 'second id seen is b');
       t.done();
     }
   });