diff --git a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
index 211c9f2d..03f954dd 100644
--- a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
+++ b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_cache_and_frames.inc
@@ -2194,7 +2194,8 @@
             auto* candidate = document.find_by_native_id(iterator->first);
             auto stale = candidate == nullptr || !is_connected(*candidate);
             if (!stale) {
-                const auto candidate_source = candidate->attributes.find("src");
+                const auto candidate_source = candidate->attributes.find(
+                    "data-webscene-remote-attempt");
                 stale = candidate_source == candidate->attributes.end()
                     || candidate_source->second != iterator->second.source
                     || current_iframe_navigation_generation(candidate->id)
@@ -2362,7 +2363,8 @@
     {
         const auto known = pending_frame_preparations.find(frame.id);
         if (known == pending_frame_preparations.end()) return {};
-        const auto source = frame.attributes.find("src");
+        const auto source = frame.attributes.find(
+            "data-webscene-remote-attempt");
         if (source == frame.attributes.end()
             || source->second != known->second.source
             || current_iframe_navigation_generation(frame.id)
@@ -2772,19 +2774,24 @@
                 && source != frame.attributes.end()) {
                 std::string html;
                 std::string resolved_name;
+                const auto attempted = frame.attributes.find(
+                    "data-webscene-remote-attempt");
+                const auto& requested = attempted == frame.attributes.end()
+                    ? source->second : attempted->second;
                 if (!load_text_resource(
-                        source->second,
+                        requested,
                         {},
                         WEBSCENE_RESOURCE_DOCUMENT,
                         html,
                         resolved_name)) {
                     frame.attributes["data-webscene-remote-result"] = "failed";
                     frame_last_error_value = "Unable to load iframe document: "
-                        + source->second;
+                        + requested;
                     ++frame_script_error_count;
                     return frame_hydration_result::failed;
                 }
-                frame.attributes["src"] = std::move(resolved_name);
+                frame.attributes["data-webscene-remote-attempt"] =
+                    std::move(resolved_name);
                 frame.attributes["object-html"] = std::move(html);
                 frame.attributes["data-webscene-remote-result"] = "loaded";
             }
@@ -2804,10 +2811,15 @@
         }
         const auto frame_source = frame.attributes.find("src");
         const auto parent_base = effective_document_base(css_cascade_root_for_node(frame));
-        const auto frame_navigation_address = frame_source != frame.attributes.end()
-            && !frame_source->second.empty()
-            ? resolve_resource_url(frame_source->second, parent_base)
-            : parent_base;
+        const auto remote_attempt = frame.attributes.find(
+            "data-webscene-remote-attempt");
+        const auto frame_navigation_address =
+            remote_attempt != frame.attributes.end()
+                ? remote_attempt->second
+                : frame_source != frame.attributes.end()
+                    && !frame_source->second.empty()
+                    ? resolve_resource_url(frame_source->second, parent_base)
+                    : parent_base;
         // Commit the replacement origin before creating its realm. The
         // outgoing realm remains authoritative throughout beforeunload and
         // unload, and the new realm cannot inherit access from reflected src.
@@ -2835,9 +2847,10 @@
                     ? std::string{}
                     : html.substr(open, close - open + 1U);
             };
-            frame_base_address = frame_source != frame.attributes.end()
-                && (frame_source->second.starts_with("http://")
-                    || frame_source->second.starts_with("https://"))
+            frame_base_address = remote_attempt != frame.attributes.end()
+                || (frame_source != frame.attributes.end()
+                    && (frame_source->second.starts_with("http://")
+                        || frame_source->second.starts_with("https://")))
                 ? frame_navigation_address
                 : parent_base;
             const auto base_opening = opening_tag("base");
diff --git a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_dom_core.inc b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_dom_core.inc
index f063dd49..97eae64e 100644
--- a/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_dom_core.inc
+++ b/experiments/WebScene.NativeEngine.Probe/native/webscene_v8_runtime_dom_core.inc
@@ -3051,11 +3051,10 @@
                     || resolved.starts_with("https://")
                     || resolved.starts_with("file://")) {
                     node.attributes["data-webscene-remote-attempt"] = resolved;
-                    node.attributes["src"] = resolved;
                     if (prefetch_iframe_documents) {
                         start_resource_prefetch(
                             resolved,
-                            {},
+                            resolved,
                             WEBSCENE_RESOURCE_DOCUMENT);
                         start_frame_preparation(node, resolved);
                         node.attributes["data-webscene-remote-result"] = "pending";
@@ -3068,6 +3067,8 @@
                                 WEBSCENE_RESOURCE_DOCUMENT,
                                 html,
                                 resolved_name)) {
+                            node.attributes["data-webscene-remote-attempt"] =
+                                std::move(resolved_name);
                             node.attributes["object-html"] = std::move(html);
                             node.attributes["data-webscene-remote-result"] = "loaded";
                         } else {
diff --git a/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_resource_tests.inc b/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_resource_tests.inc
index 4f224efb..892c1699 100644
--- a/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_resource_tests.inc
+++ b/experiments/WebScene.NativeEngine.Probe/tests/native_v8_runtime_resource_tests.inc
@@ -312,7 +312,7 @@ void test_same_origin_iframe_navigation_document_replacement()
         complete:false, error:null, beforeunload:0, pagehide:0,
         visibilitychange:0, unload:0, order:[],
         synchronous:true, eventShape:true, vetoPreserved:false,
-        reentrantBlocked:false, reentrantUnloadBlocked:false,
+        reentrantBlocked:false, reentrantUnloadBlocked:false, observedSource:null,
         visibilityHidden:false, lifecycleIdentity:true, taskRan:false,
         allowedLoaded:false, stableProxy:false
       };
@@ -414,7 +414,8 @@ void test_same_origin_iframe_navigation_document_replacement()
                   && state.pagehide === 1
                   && state.visibilitychange === 1
                   && state.unload === 1;
-                state.reentrantUnloadBlocked = frame.getAttribute('src')
+                state.observedSource = frame.getAttribute('src');
+                state.reentrantUnloadBlocked = state.observedSource
                   === './fake.html?id=allowed'
                   && state.order.join(',')
                     === 'beforeunload,pagehide,visibilitychange,unload';
@@ -461,7 +462,9 @@ void test_same_origin_iframe_navigation_document_replacement()
                 "iframe-beforeunload-result-detail.js"));
     require(server.requests.load(std::memory_order_relaxed)
             == requests_before_unload_ordering + 2,
-        "reentrant unload navigation admitted an unexpected resource request");
+        "reentrant unload navigation admitted an unexpected resource request: before="
+            + std::to_string(requests_before_unload_ordering) + " after="
+            + std::to_string(server.requests.load(std::memory_order_relaxed)));
     const auto requests_before_detach_unload = server.requests.load(
         std::memory_order_relaxed);
     execute(engine, R"JS(