diff --git a/tests/README.md b/tests/README.md
index 27f9932..ca987ed 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -246,6 +246,12 @@ Linux, and macOS with Python 3.13 and PySide6 6.8.3. The publication workflow re
 that job before PyPI publication. Opt-in tests and packaged/manual smoke checks remain
 separate; local Windows results do not establish the other CI targets.
 
+The settings harness compares canonical paths on every access so macOS temporary-directory
+aliases and Windows short names do not look like sandbox escapes. Its isolation regressions
+cover an aliased root and rejection of paths outside that root. The QR responsiveness test
+queues unrelated work after generation starts and requires delivery before completion;
+it does not assume a platform-specific order between zero-delay Qt timers.
+
 The Home/Log workflow regressions exercise debounced typing, explicit submit/clear, navigation catch-up, focus-scoped
 Find/edit shortcuts, and live log filtering. These are real Qt tests in `test_qt_interactions.py` and
 `test_ui_behavior.py`; no production log source or profile network is started. The two optional pause regressions
diff --git a/tests/support.py b/tests/support.py
index 74c2c93..35cc2a6 100644
--- a/tests/support.py
+++ b/tests/support.py
@@ -108,7 +108,9 @@ def _initializeSettingsSandbox():
     global _settingsDirectory
 
     if _settingsDirectory is not None:
-        return Path(_settingsDirectory.name)
+        # TemporaryDirectory may retain a macOS /var alias or Windows short
+        # path. Match the canonical root used on initialization and by Qt.
+        return Path(_settingsDirectory.name).resolve()
 
     _settingsDirectory = tempfile.TemporaryDirectory(
         prefix='furious-tests-settings-root-'
diff --git a/tests/test_isolation_and_navigation.py b/tests/test_isolation_and_navigation.py
index 19b1440..c45f4ca 100644
--- a/tests/test_isolation_and_navigation.py
+++ b/tests/test_isolation_and_navigation.py
@@ -26,6 +26,9 @@ from PySide6.QtTest import QTest
 from PySide6.QtWidgets import QPushButton, QVBoxLayout, QWidget
 
 from pathlib import Path
+from unittest import mock
+
+import tests.support as SupportModule
 
 from tests.support import (
     application,
@@ -58,7 +61,9 @@ class TestHarnessIsolationTest(unittest.TestCase):
 
             assertIsolatedSettings(outer)
 
-            self.assertIn(settingsSandboxPath(), Path(outer.fileName()).parents)
+            self.assertIn(
+                settingsSandboxPath(), Path(outer.fileName()).resolve().parents
+            )
 
             with isolatedSettings() as inner:
                 innerIdentity = (app.organizationName(), app.applicationName())
@@ -87,7 +92,35 @@ class TestHarnessIsolationTest(unittest.TestCase):
 
         assertIsolatedSettings(settings)
 
-        self.assertIn(settingsSandboxPath(), Path(settings.fileName()).parents)
+        self.assertIn(
+            settingsSandboxPath(), Path(settings.fileName()).resolve().parents
+        )
+
+    def testExistingSandboxRootUsesTheSameCanonicalPath(self):
+        """Normalize reused temporary-directory aliases before containment checks."""
+        root = settingsSandboxPath().resolve()
+        alias = root / '..' / root.name
+
+        # TemporaryDirectory.name can retain an alias even though QSettings
+        # returns the canonical path (macOS /var or Windows short user names).
+        with mock.patch.object(SupportModule._settingsDirectory, 'name', str(alias)):
+            self.assertEqual(settingsSandboxPath(), root)
+
+            with isolatedSettings() as settings:
+                assertIsolatedSettings(settings)
+                settings.setValue('alias-fixture', 'isolated')
+                settings.sync()
+                self.assertEqual(settings.value('alias-fixture'), 'isolated')
+
+    def testSettingsOutsideSandboxAreStillRejected(self):
+        """Reject a sibling path even when its name shares the sandbox prefix."""
+        root = settingsSandboxPath().resolve()
+        outside = root.with_name(root.name + '-outside') / 'settings.ini'
+        settings = QtCore.QSettings(str(outside), QtCore.QSettings.Format.IniFormat)
+
+        # Constructing this object does not write; rejection must precede writes.
+        with self.assertRaisesRegex(AssertionError, 'escaped sandbox'):
+            assertIsolatedSettings(settings)
 
 
 class NavigationBehaviorTest(unittest.TestCase):
diff --git a/tests/test_qr_export_scalability.py b/tests/test_qr_export_scalability.py
index 0dc4b71..86a79f3 100644
--- a/tests/test_qr_export_scalability.py
+++ b/tests/test_qr_export_scalability.py
@@ -168,7 +168,7 @@ class QRCodeExportScalabilityTest(unittest.TestCase):
                 self.assertEqual(appendExportItem.call_count, expected)
 
     def testGenerationYieldsToAnUnrelatedQtEvent(self):
-        """Deliver unrelated work after one attempt and before batch completion."""
+        """Deliver unrelated work during generation, before batch completion."""
         profiles = self.profiles(6)
         attempts = []
         marker = []
@@ -178,6 +178,12 @@ class QRCodeExportScalabilityTest(unittest.TestCase):
             """Record one exported snapshot."""
             attempts.append(profile.itemRemark)
 
+            if len(attempts) == 1:
+                # Zero-timer ordering is platform-dependent. Queue the marker
+                # only once generation has started, then require it to run
+                # before all profiles finish rather than after exactly one.
+                QtCore.QTimer.singleShot(0, lambda: marker.append(len(attempts)))
+
             return f'socks://{len(attempts)}.example:1080#Fixture'
 
         with mock.patch(
@@ -191,13 +197,14 @@ class QRCodeExportScalabilityTest(unittest.TestCase):
             side_effect=self.qrImage,
         ):
             result = window.startExportByIndex(range(len(profiles)))
-            QtCore.QTimer.singleShot(0, lambda: marker.append(len(attempts)))
 
             self.assertIs(result, window)
             self.assertEqual(attempts, [])
             self.assertTrue(window.isVisible())
             self.assertTrue(waitFor(lambda: bool(marker)))
-            self.assertEqual(marker, [1])
+            self.assertEqual(len(marker), 1)
+            self.assertGreaterEqual(marker[0], 1)
+            self.assertLess(marker[0], len(profiles))
             self.assertTrue(waitFor(lambda: not window.isExporting()))
 
         self.assertEqual(len(attempts), len(profiles))