Problem Description: When a router is configured with options:dynamic-routing-redistribute=connected-as-host then even nat entries create their records in the SB Advertised_Routes table. That creates a problem if also the 'nat' option is added to the redistribute option. Then the northd ends up in an endless loop attempting to create the same entry in Advertised_Routes twice and failing.

2025-07-29T15:34:31.665Z|00092|ovsdb_idl|WARN|transaction error: {"details":"Transaction causes multiple rows in \"Advertised_Route\" table to have identical values (d55c1c4d-3a26-4778-a4df-ac66cc656f4c, 06bdfdaf-860c-43ff-aca5-d85b3cb36c 87, \"192.168.111.175\", and 74263727-26b5-499c-ac27-02b319519b33) for index on columns \"datapath\", \"logical_port\", \"ip_prefix\", and \"tracked_port\". First row, with UUID 62b19c1d-cc31-45e3-bee8-fff66f493e89, existed in the databa se before this transaction and was not modified by the transaction. Second row, with UUID fd53805d-7f9b-402c-9ff5-da00bbdef7a3, was inserted by this transaction.","error":"constraint violation"}

 Impact Assessment: northd is stuck if both entries connected-as-host and nat are defined. workaround is to remove the 'nat' option.

 Software Versions: ovn 25.03

  Issue Type: new issue

 Reproducibility: reproducible easily

 Reproduction Steps: Have a router with a nat entry and configure options:dynamic-routing-redistribute=connected-as-host,nat

 Expected Behavior: advertised-routes from the nat entries should be created only if nat option is present

 Observed Behavior: if connected-as-host is configured then also IPs from external_ip nat entries appear