diff --git a/gateway/run.py b/gateway/run.py
index aa999b53a992..6b4e64b091d6 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -10342,12 +10342,15 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
                 if owner is not None:
                     logger.error(
                         "Profile '%s' and '%s' both configure %s with the same "
-                        "credential — refusing to start the duplicate (a single "
-                        "bot token cannot be polled twice). Give each profile its "
-                        "own %s credential.",
+                        "credential — refusing to start the duplicate (one "
+                        "credential cannot be consumed twice). Give each profile "
+                        "its own %s credential.",
                         owner, profile_name, platform.value, platform.value,
                     )
-                    await self._safe_adapter_disconnect(adapter, platform)
+                    # This adapter has not connected and therefore owns no
+                    # resources to clean up. Calling disconnect here can mutate
+                    # the shared platform state and, for a same-credential Photon
+                    # adapter, shut down the primary profile's live sidecar.
                     continue
                 claimed[(platform, fp)] = profile_name
 
@@ -10591,13 +10594,23 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
     def _adapter_credential_fingerprint(adapter: Any) -> Optional[str]:
         """Return a stable, log-safe fingerprint of an adapter's credential.
 
-        Used only to detect two profiles claiming the same bot token. Returns a
-        salted hash (never the token itself) of the adapter's primary
-        credential, or None when no credential is discoverable (in which case
-        we don't attempt conflict detection for it).
+        Used only to detect two profiles claiming the same platform credential.
+        Returns a salted hash (never the credential itself) of the adapter's
+        primary credential, or None when no credential is discoverable (in
+        which case we don't attempt conflict detection for it).
         """
         token = None
-        for attr in ("token", "bot_token", "_token", "api_token", "_bot_token"):
+        for attr in (
+            "token",
+            "bot_token",
+            "_token",
+            "api_token",
+            "_bot_token",
+            # Photon/Spectrum authenticates with project credentials instead
+            # of a bot token. Including its secret keeps multiplexed profiles
+            # from spawning competing sidecars for the same account and port.
+            "_project_secret",
+        ):
             val = getattr(adapter, attr, None)
             if isinstance(val, str) and val.strip():
                 token = val.strip()
diff --git a/tests/gateway/test_multiplex_adapter_registry.py b/tests/gateway/test_multiplex_adapter_registry.py
index 2b228943790c..885ac3a67659 100644
--- a/tests/gateway/test_multiplex_adapter_registry.py
+++ b/tests/gateway/test_multiplex_adapter_registry.py
@@ -41,6 +41,22 @@ class TestCredentialFingerprint:
                 self.bot_token = "alt-token"
         assert GatewayRunner._adapter_credential_fingerprint(_AltAdapter()) is not None
 
+    def test_reads_photon_project_secret(self):
+        class _PhotonAdapter:
+            def __init__(self, secret):
+                self._project_secret = secret
+
+        fp1 = GatewayRunner._adapter_credential_fingerprint(
+            _PhotonAdapter("shared-project-secret")
+        )
+        fp2 = GatewayRunner._adapter_credential_fingerprint(
+            _PhotonAdapter("shared-project-secret")
+        )
+
+        assert fp1 == fp2
+        assert fp1 is not None
+        assert "shared-project-secret" not in fp1
+
     def test_reads_platform_config_token(self):
         class _Config:
             token = "config-token"
@@ -718,8 +734,10 @@ class TestSecondaryProfileConfigHandling:
         assert connect_calls == [(relay, Platform.RELAY)]
 
     @pytest.mark.asyncio
-    async def test_secondary_same_config_token_is_refused(self, monkeypatch):
-        """Adapters that keep their token on config still trip the mux guard."""
+    async def test_secondary_same_config_token_is_refused_without_disconnect(
+        self, monkeypatch
+    ):
+        """A never-connected duplicate must not disturb shared live state."""
         from gateway.config import GatewayConfig, Platform, PlatformConfig
 
         class _ConfigTokenAdapter:
@@ -762,7 +780,7 @@ class TestSecondaryProfileConfigHandling:
         )
 
         assert connected == 0
-        assert duplicate.disconnected is True
+        assert duplicate.disconnected is False
         assert runner._profile_adapters["reviewer"] == {}
 
     def test_port_binding_set_covers_known_listeners(self):