Bug in DataTable Select logic?

So found a really odd issue in the DataTable Select method.  Here's code from a console app that demonstrates it:

 string filterSt = "event_id=203518 AND (1=1 and not(event_id=203518))";
            DataTable dt = new DataTable();
            dt.Columns.AddRange(
                new[] { new DataColumn("event_id", typeof(int)), new DataColumn("venue_id", typeof(int)) });
            dt.Rows.Add(203518, 1356);

            foreach (var dr in dt.Select(filterSt))
            {
                Console.WriteLine("This should not appear");
            }

            Console.WriteLine("done");
            Console.ReadKey();

What's really odd is that if you change the filter string to this, it works correctly:

            string filterSt = "1=1 AND (1=1 and not(event_id=203518))";

Am I going crazy or is this a bug in .NET?