Inserts in Oracle table with array binding and CLOB is very slow

I have the problem that inserting into an Oracle table takes a very long time when using CLOBs or BLOBs. I use array binding (see example below) and the .Net Oracle managed driver. As soon as the OracleDbType Clob or Blob is used the insert speed decreases massively. If I change the type to Varchar2 it runs very fast. Unfortunately this is not the solution because we have strings that can become very long.

It looks like as soon as I use the OracleDbType Clob, single inserts are executed.

Do I miss a setting or is it a bug or a documented behavior?

Insert of 1000 records (see example):

Data insert clob: 4,3272996
Data insert Varchar: 0,0231472

Example:

Create table with lob:

CREATE TABLE EXAMPLE_DATA
(
    ID NUMBER,
    DATA CLOB
);

Unittest

        [Fact]
        public void ExampleArrayBinding()
        {
            Stopwatch s = new Stopwatch();
            using (var connection = new OracleConnection(conString))
            {
                connection.Open();
                using (OracleCommand cmd = connection.CreateCommand())
                {
                    cmd.CommandText = "INSERT INTO EXAMPLE_DATA VALUES(:id, :data)";

                    // Add parameters to command parameters collection
                    cmd.Parameters.Add("id", OracleDbType.Int16);
                    cmd.Parameters.Add("data", OracleDbType.Clob);

                    // Set parameters values
                    cmd.Parameters["id"].Value = Enumerable.Range(1, 1000).ToArray();
                    cmd.Parameters["data"].Value = Enumerable.Range(1, 1000).Select(x => $"a{x}").ToArray();
                    cmd.ArrayBindCount = 1000;

                    //clob Parameter
                    this.TruncateTable("EXAMPLE_DATA", connection);
                    s.Start();
                    cmd.ExecuteNonQuery();
                    s.Stop();
                    this.output.WriteLine("Data insert clob: " + s.Elapsed.TotalSeconds);

                    //varchar2 Parameter
                    this.TruncateTable("EXAMPLE_DATA", connection);
                    s.Restart();
                    cmd.Parameters["data"].OracleDbType = OracleDbType.Varchar2;
                    cmd.ExecuteNonQuery();
                    s.Stop();
                    this.output.WriteLine("Data insert Varchar: " + s.Elapsed.TotalSeconds);
                }
            }

        }