diff --git a/api/helpers.py b/api/helpers.py
index 5c984f0..fd04bda 100644
--- a/api/helpers.py
+++ b/api/helpers.py
@@ -211,17 +211,19 @@ def get_profile_cookie(handler) -> str | None:
 def build_profile_cookie(name: str) -> str:
     """Build a Set-Cookie header value for the hermes_profile cookie.
 
-    name='default' clears the cookie (max-age=0).
-    Any other valid profile name sets it for the browser session.
-    httponly=True: the JS reads profile from /api/profile/active JSON, never
-    from document.cookie, so httponly exposure is unnecessary.
+    Always persist the selected profile in the cookie, including 'default'.
+    Clearing the cookie causes the backend to fall back to process-global
+    _active_profile, which can unexpectedly switch clients back to another
+    profile.
+
+    Set HttpOnly because the UI reads the active profile from
+    /api/profile/active JSON and does not need to access this cookie via
+    document.cookie.
     """
     import http.cookies as _hc
     cookie = _hc.SimpleCookie()
-    cookie[PROFILE_COOKIE_NAME] = '' if name == 'default' else name
+    cookie[PROFILE_COOKIE_NAME] = name
     cookie[PROFILE_COOKIE_NAME]['path'] = '/'
     cookie[PROFILE_COOKIE_NAME]['httponly'] = True
     cookie[PROFILE_COOKIE_NAME]['samesite'] = 'Lax'
-    if name == 'default':
-        cookie[PROFILE_COOKIE_NAME]['max-age'] = '0'
     return cookie[PROFILE_COOKIE_NAME].OutputString()
diff --git a/static/panels.js b/static/panels.js
index e9a48d6..885d5c1 100644
--- a/static/panels.js
+++ b/static/panels.js
@@ -843,6 +843,9 @@ async function loadProfilesPanel() {
       panel.innerHTML = `<div style="padding:16px;color:var(--muted);font-size:12px">${esc(t('profiles_no_profiles'))}</div>`;
       return;
     }
+    const activeName = (S.activeProfile && data.profiles.some(p => p.name === S.activeProfile))
+      ? S.activeProfile
+      : (data.active || 'default');
     for (const p of data.profiles) {
       const card = document.createElement('div');
       card.className = 'profile-card';
@@ -854,7 +857,7 @@ async function loadProfilesPanel() {
       const gwDot = p.gateway_running
         ? `<span class="profile-opt-badge running" title="${esc(t('profile_gateway_running'))}"></span>`
         : `<span class="profile-opt-badge stopped" title="${esc(t('profile_gateway_stopped'))}"></span>`;
-      const isActive = p.name === data.active;
+      const isActive = p.name === activeName;
       const activeBadge = isActive ? `<span style="color:var(--link);font-size:10px;font-weight:600;margin-left:6px">${esc(t('profile_active'))}</span>` : '';
       const defaultBadge = p.is_default ? ` <span style="opacity:.5">${esc(t('profile_default_label'))}</span>` : '';
       card.innerHTML = `
@@ -880,7 +883,9 @@ function renderProfileDropdown(data) {
   if (!dd) return;
   dd.innerHTML = '';
   const profiles = data.profiles || [];
-  const active = data.active || 'default';
+  const active = (S.activeProfile && profiles.some(p => p.name === S.activeProfile))
+    ? S.activeProfile
+    : (data.active || 'default');
   for (const p of profiles) {
     const opt = document.createElement('div');
     opt.className = 'profile-opt' + (p.name === active ? ' active' : '');
@@ -1005,7 +1010,9 @@ async function switchToProfile(name) {
           S.session.workspace = S._profileDefaultWorkspace;
         } catch (_) {}
       }
-      updateWorkspaceChip();
+      // Keep topbar chips (workspace/profile) in sync after creating the
+      // new profile-scoped session.
+      syncTopbar();
       await renderSessionList();
       showToast(t('profile_switched_new_conversation', name));
     } else {
diff --git a/tests/test_issue803.py b/tests/test_issue803.py
index 9190362..f882e14 100644
--- a/tests/test_issue803.py
+++ b/tests/test_issue803.py
@@ -33,12 +33,11 @@ class TestProfileCookieHelpers:
         assert 'SameSite=Lax' in s
         assert 'Path=/' in s
 
-    def test_build_profile_cookie_default_clears(self):
+    def test_build_profile_cookie_default_persists(self):
         from api.helpers import build_profile_cookie
         s = build_profile_cookie('default')
-        assert 'Max-Age=0' in s
-        # Empty value indicates clear
-        assert 'hermes_profile=""' in s or 'hermes_profile=;' in s
+        assert 'hermes_profile=default' in s
+        assert 'Max-Age=0' not in s
 
     def test_get_profile_cookie_returns_none_when_absent(self):
         from api.helpers import get_profile_cookie
diff --git a/tests/test_sprint40_ui_polish.py b/tests/test_sprint40_ui_polish.py
index 0cb798f..b71141c 100644
--- a/tests/test_sprint40_ui_polish.py
+++ b/tests/test_sprint40_ui_polish.py
@@ -202,10 +202,10 @@ class TestWorkspaceChipAfterProfileSwitch(unittest.TestCase):
     """Verify that switchToProfile() applies the profile default workspace
     to the new session when a conversation is in progress (fixes #424)."""
 
-    def test_workspace_chip_updated_after_profile_switch(self):
+    def test_topbar_synced_after_profile_switch(self):
         """After await newSession(false) in the sessionInProgress branch,
-        the code must call updateWorkspaceChip() so the chip reflects the
-        new profile's default workspace instead of showing 'No active workspace'."""
+        the code must call syncTopbar() so the profile/workspace chips reflect
+        the new profile's default workspace."""
         # Find the sessionInProgress block
         idx = PANELS_JS.find('if (sessionInProgress)')
         self.assertGreater(idx, -1, "sessionInProgress branch must exist in panels.js")
@@ -217,13 +217,13 @@ class TestWorkspaceChipAfterProfileSwitch(unittest.TestCase):
         self.assertIn('await newSession(false)', block,
                       "sessionInProgress branch must call await newSession(false)")
 
-        # The fix: updateWorkspaceChip() must be called after newSession(false)
+        # The fix: syncTopbar() must be called after newSession(false)
         pos_new_session = block.find('await newSession(false)')
-        pos_update_chip = block.find('updateWorkspaceChip()')
-        self.assertGreater(pos_update_chip, -1,
-                           "updateWorkspaceChip() must be called in the sessionInProgress branch")
-        self.assertGreater(pos_update_chip, pos_new_session,
-                           "updateWorkspaceChip() must be called AFTER newSession(false)")
+        pos_sync_topbar = block.find('syncTopbar()')
+        self.assertGreater(pos_sync_topbar, -1,
+                           "syncTopbar() must be called in the sessionInProgress branch")
+        self.assertGreater(pos_sync_topbar, pos_new_session,
+                           "syncTopbar() must be called AFTER newSession(false)")
 
     def test_profile_default_workspace_applied_to_new_session(self):
         """After newSession(false) the code must assign S._profileDefaultWorkspace
@@ -248,19 +248,19 @@ class TestWorkspaceChipAfterProfileSwitch(unittest.TestCase):
                       "The sessionInProgress branch must call /api/session/update "
                       "to persist the new workspace after newSession(false)")
 
-    def test_update_workspace_chip_before_render_session_list(self):
-        """updateWorkspaceChip() should be called before renderSessionList()
-        so the chip is correct when the UI re-renders."""
+    def test_sync_topbar_before_render_session_list(self):
+        """syncTopbar() should be called before renderSessionList()
+        so the chips are correct when the UI re-renders."""
         idx = PANELS_JS.find('if (sessionInProgress)')
         self.assertGreater(idx, -1)
         block = PANELS_JS[idx:idx + 1000]
 
-        pos_chip = block.find('updateWorkspaceChip()')
+        pos_sync = block.find('syncTopbar()')
         pos_render = block.find('await renderSessionList()')
-        self.assertGreater(pos_chip, -1, "updateWorkspaceChip() must exist in block")
+        self.assertGreater(pos_sync, -1, "syncTopbar() must exist in block")
         self.assertGreater(pos_render, -1, "renderSessionList() must exist in block")
-        self.assertLess(pos_chip, pos_render,
-                        "updateWorkspaceChip() must be called before renderSessionList()")
+        self.assertLess(pos_sync, pos_render,
+                        "syncTopbar() must be called before renderSessionList()")
 
 
 if __name__ == '__main__':