In --configOnly mode, mongos rejects reads on fixed namespaces such as admin.system.version and config.settings with error 12319006 because resolving the config shard goes through the catalog-backed shard registry refresh path, which is intentionally blocked in config-only mode.

These reads should be routed to the config server, since the config server itself does not run with --configOnly restrictions. The fix should allow config-shard resolution from _configShardData without enabling access to data shards or tracked namespaces such as config.system.sessions.