diff --git a/backend/app/services/device_discovery.py b/backend/app/services/device_discovery.py
index 63c3ba2..8651513 100644
--- a/backend/app/services/device_discovery.py
+++ b/backend/app/services/device_discovery.py
@@ -646,15 +646,10 @@ async def discover_via_ssh(
             result.errors.append(f"SSH to {rack_host} failed: {exc}")
             rack_ssh_ok = False
             config_text = None
-        logger.info(f"[ssh_discovery] Processing rack {rack_host} ({rack_hostname})")
+        logger.info(f"[ssh_discovery] Processing rack {rack_host} ({rack_hostname}), ssh_ok={rack_ssh_ok}, in_db={existing_rack_pc is not None}")
+        # Reuse existing_rack_pc (queried before SSH) — same identity map object
+        existing_rack = existing_rack_pc
         try:
-            existing_rack = (await db.execute(
-                select(Device).where(
-                    Device.object_id == obj.id,
-                    Device.ip == rack_host,
-                )
-            )).scalar_one_or_none()
-
             if existing_rack is None:
                 db.add(Device(
                     object_id=obj.id,
@@ -724,7 +719,10 @@ async def discover_via_ssh(
                 role="other",
             ))
         if not rack_ssh_ok:
-            await db.flush()
+            try:
+                await db.flush()
+            except Exception as exc:
+                result.errors.append(f"Flush error for offline rack {rack_host}: {exc}")
             continue  # no config to parse
 
         # Get all rack IPs to exclude them from device discovery