diff --git a/dom/tests/browser/browser.ini b/dom/tests/browser/browser.ini
index 91f7731c2d50..ad36049e7b33 100644
--- a/dom/tests/browser/browser.ini
+++ b/dom/tests/browser/browser.ini
@@ -106,6 +106,5 @@ support-files =
 [browser_keypressTelemetry.js]
 skip-if = webrender
 [browser_windowProxy_transplant.js]
-skip-if = (!fission && (os == 'linux' || os == 'mac')) || (fission && os == 'linux' && bits == 64 && os_version == '18.04') # Bug 1582568; Bug 1581862, bug 1608600 
 support-files =
   file_postMessage_parent.html
diff --git a/js/src/proxy/CrossCompartmentWrapper.cpp b/js/src/proxy/CrossCompartmentWrapper.cpp
index 547aa5c9370c..106201abc397 100644
--- a/js/src/proxy/CrossCompartmentWrapper.cpp
+++ b/js/src/proxy/CrossCompartmentWrapper.cpp
@@ -526,8 +526,6 @@ void js::RemapWrapper(JSContext* cx, JSObject* wobjArg,
   MOZ_ASSERT(!newTarget->is<CrossCompartmentWrapperObject>());
   JSObject* origTarget = Wrapper::wrappedObject(wobj);
   MOZ_ASSERT(origTarget);
-  MOZ_ASSERT(!JS_IsDeadWrapper(origTarget),
-             "We don't want a dead proxy in the wrapper map");
   JS::Compartment* wcompartment = wobj->compartment();
   MOZ_ASSERT(wcompartment != newTarget->compartment());
 
@@ -548,6 +546,14 @@ void js::RemapWrapper(JSContext* cx, JSObject* wobjArg,
   // When we remove origv from the wrapper map, its wrapper, wobj, must
   // immediately cease to be a cross-compartment wrapper. Nuke it.
   NukeCrossCompartmentWrapper(cx, wobj);
+
+  // If the target is a dead wrapper, and we're just fixing wrappers for
+  // it, then we're done now that the CCW is a dead wrapper.
+  if (JS_IsDeadWrapper(origTarget)) {
+    MOZ_RELEASE_ASSERT(origTarget == newTarget);
+    return;
+  }
+
   js::RemapDeadWrapper(cx, wobj, newTarget);
 }
 
diff --git a/js/xpconnect/wrappers/WrapperFactory.cpp b/js/xpconnect/wrappers/WrapperFactory.cpp
index b318b8db5242..f04e339703d0 100644
--- a/js/xpconnect/wrappers/WrapperFactory.cpp
+++ b/js/xpconnect/wrappers/WrapperFactory.cpp
@@ -826,6 +826,11 @@ static void NukeXrayWaiver(JSContext* cx, JS::HandleObject obj) {
   scope->mWaiverWrapperMap->Remove(key);
 
   js::NukeNonCCWProxy(cx, waiver);
+
+  // Get rid of any CCWs the waiver may have had.
+  if (!JS_RefreshCrossCompartmentWrappers(cx, waiver)) {
+    MOZ_CRASH();
+  }
 }
 
 JSObject* TransplantObjectNukingXrayWaiver(JSContext* cx,