I believe I have found a bug with the logic of how a prepared statement is cached in the StatementFactory in the Cassandra csharp driver (version 2.7.3). Here is the use cas
As a simple workaround, I am skipping the cache by using the DoNotPrepare
await _mapper.DeleteAsync(Cql.New("WHERE id = ?", key).WithOptions(opt => opt.DoNotPrepare()));
I also found an open issue with Datastax