diff --git a/browser/base/content/test/about/browser.ini b/browser/base/content/test/about/browser.ini
index 467ae61ca7b8..e06776932819 100644
--- a/browser/base/content/test/about/browser.ini
+++ b/browser/base/content/test/about/browser.ini
@@ -27,3 +27,4 @@ skip-if = os == "mac" || (os == "linux" && (!debug || bits == 64)) || (os == 'wi
 [browser_aboutSupport_newtab_security_state.js]
 [browser_bug435325.js]
 skip-if = fission || (verify && !debug && os == 'mac')
+[browser_bug633691.js]
diff --git a/browser/base/content/test/about/browser_bug633691.js b/browser/base/content/test/about/browser_bug633691.js
new file mode 100644
index 000000000000..614ad79fd795
--- /dev/null
+++ b/browser/base/content/test/about/browser_bug633691.js
@@ -0,0 +1,32 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+add_task(async function test() {
+  const URL = "data:text/html,<iframe width='700' height='700'></iframe>";
+  await BrowserTestUtils.withNewTab({ gBrowser, url: URL }, async function(
+    browser
+  ) {
+    let context = await ContentTask.spawn(browser, null, function() {
+      let iframe = content.document.querySelector("iframe");
+      iframe.src = "https://expired.example.com/";
+      return BrowsingContext.getFromWindow(iframe.contentWindow);
+    });
+    await TestUtils.waitForCondition(() => {
+      let frame = context.currentWindowGlobal;
+      info(frame.documentURI.spec);
+      return frame && frame.documentURI.spec.startsWith("about:certerror");
+    });
+    await SpecialPowers.spawn(context, [], async function() {
+      await ContentTaskUtils.waitForCondition(
+        () => content.document.readyState == "interactive"
+      );
+      let aP = content.document.getElementById("badCertAdvancedPanel");
+      Assert.ok(aP, "Advanced content should exist");
+      Assert.ok(
+        ContentTaskUtils.is_hidden(aP),
+        "Advanced content should not be visible by default"
+      );
+    });
+  });
+});
diff --git a/browser/base/content/test/general/browser.ini b/browser/base/content/test/general/browser.ini
index f830edcfb473..429af4a5092a 100644
--- a/browser/base/content/test/general/browser.ini
+++ b/browser/base/content/test/general/browser.ini
@@ -192,9 +192,6 @@ skip-if = (verify && debug && (os == 'linux'))
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_bug624734.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
-[browser_bug633691.js]
-# DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
-skip-if = fission
 [browser_bug647886.js]
 # DO NOT ADD MORE TESTS HERE. USE A TOPICAL DIRECTORY INSTEAD.
 [browser_bug664672.js]
diff --git a/browser/base/content/test/general/browser_bug633691.js b/browser/base/content/test/general/browser_bug633691.js
deleted file mode 100644
index 8042500dde2e..000000000000
--- a/browser/base/content/test/general/browser_bug633691.js
+++ /dev/null
@@ -1,45 +0,0 @@
-/* Any copyright is dedicated to the Public Domain.
- * http://creativecommons.org/publicdomain/zero/1.0/
- */
-
-add_task(async function test() {
-  const URL = "data:text/html,<iframe width='700' height='700'></iframe>";
-  await BrowserTestUtils.withNewTab({ gBrowser, url: URL }, async function(
-    browser
-  ) {
-    await ContentTask.spawn(
-      browser,
-      {
-        is_element_hidden_: is_element_hidden.toSource(),
-        is_hidden_: is_hidden.toSource(),
-      },
-      async function({ is_element_hidden_, is_hidden_ }) {
-        let loadError = ContentTaskUtils.waitForEvent(
-          this,
-          "AboutNetErrorLoad",
-          false,
-          null,
-          true
-        );
-        let iframe = content.document.querySelector("iframe");
-        iframe.src = "https://expired.example.com/";
-
-        await loadError;
-
-        /* eslint-disable no-eval */
-        let is_hidden = eval(`(() => ${is_hidden_})()`);
-        let is_element_hidden = eval(`(() => ${is_element_hidden_})()`);
-        /* eslint-enable no-eval */
-        let doc = content.document.getElementsByTagName("iframe")[0]
-          .contentDocument;
-        let aP = doc.getElementById("badCertAdvancedPanel");
-        ok(aP, "Advanced content should exist");
-        void is_hidden; // Quiet eslint warnings (actual use under is_element_hidden)
-        is_element_hidden(
-          aP,
-          "Advanced content should not be visible by default"
-        );
-      }
-    );
-  });
-});