SingleQuery is able to execute transaction without sufficient RBAC permissions

public static void main(String[] args) {

    JsonObject initialQuery = JsonObject.create().put("content", "initial-query");

    //Connect as Administrator

    Cluster cluster = Cluster.connect("localhost","Administrator", "password");

    // create a rbac user with "query_insert" role on transaction operation collection i.e collection_transactionOps

    // Note that This user has no permissions at all on metadataCollection and default collection

    User user = new User("query_insert_user")

            .password("password")

            .roles(new Role("query_insert", "default", "custom_scope","collection_transactionOps"));

    cluster.users().upsertUser(user);

    cluster.disconnect();

    //Now connect as the rbac user

    TransactionKeyspace keyspace =TransactionKeyspace.create("default","custom_scope","metadataCollection");

    ClusterEnvironment env = ClusterEnvironment.builder()

            // Adding metadata collection for transactions

            .transactionsConfig(TransactionsConfig.builder().metadataCollection(keyspace))

            .build();

    Cluster newcluster = Cluster.connect("localhost",ClusterOptions.clusterOptions("query_insert_user", "password").environment(env));

    try{

        String docId = UUID.randomUUID().toString();

        String queryStmt = "INSERT INTO `default`.`custom_scope`.`collection_transactionOps` VALUES ('" + docId + "', " + initialQuery + ")";

        newcluster.query(queryStmt);

        // This docId is not supposed to be present but I could see in UI its present in `default`.`custom_scope`.`collection_transactionOps`. You can add any assertion here

        System.out.println("DocId: "+docId);

        System.out.println("queryStmt: "+queryStmt);

    }catch (TransactionFailedException e){

        System.out.println("Caught TransactionFailedException:");

        // Some exception handling

    }catch (CouchbaseException ce){

        System.out.println("Caught CouchbaseException: "+ce);

    }catch (RuntimeException re){

        System.out.println("Caught RuntimeException:");

    }

}