When cleanup_collection.js is run sharding_jscore_passthrough_with_config_transitions, bulk writes may be interrupted due to movePrimary. When the bulk write is retried by https://github.com/mongodb/mongo/blob/0c94927109991bfe4b474e4f7a3188185cdcd445/jstests/libs/override_methods/implicitly_retry_on_shard_transition_errors.js#L105-L121, the retry was failing since the first insert gets marked as a duplicate and not all rows get inserted.