During the execution of CheckMetadataConsistency command (cluster level)  each shard perform a read on config.databases on the config server with ReadPreference::nearest to understand which are the databases they are primary for (db primary shard).

Once we complete SPM-3729 we should be able to substitute this remote read with a local read. In fact, each shard will be able to understand which are the databases they are primary for, by reading from config.shardLocal.catalog.databases.