System.ArgumentException: 'Builder not correctly implemented'

Just stared getting this error after updating to Zebra.Printer.SDK v2.15.2634 from 2.14.1989

C# sample code

   string conn = null;

   foreach (DiscoveredPrinterDriver zPrinter in UsbDiscoverer.GetZebraDriverPrinters())
   {
    conn = zPrinter.GetConnection().ToString();
   }

   if ( Sys.PartNumberModel.CompanyName == "Hi")
   {
    PrinterUtil.SendContents(conn, "^XA"); <== get error here
    PrinterUtil.SendContents(conn, "^FO40,40^BY2^B3N,N,75,N,N^FD" + Sys.SerialNumber + "^FS");
    PrinterUtil.SendContents(conn, "^FO40,130^ASN,28,15^FD" + "SN:" + Sys.SerialNumber + "^FS");
    PrinterUtil.SendContents(conn, "^FO300,130^ASN,28,15^FD" + "WO:" + Sys.WorkOrder + "^FS");
    PrinterUtil.SendContents(conn, "^FO40,175^A2,28,15^FD" + "PN:" + Sys.PartNumberModel.PartNumber + "^FS");
    PrinterUtil.SendContents(conn, "^FO300,175^A2,28,15^FD" + "TS:" + Sys.PartNumberModel.SpecNumber + "^FS");
    PrinterUtil.SendContents(conn, "^FO40,205^A2,28,15^FD" + "FW:" + Sys.HearingAid.Algorithm_Version + "^FS");
    PrinterUtil.SendContents(conn, "^FO300,205^A2,28,15^FD" + "Test: " + Global.SoftWareVersion + " " + Global.SoftWareRevision + "^FS");
    PrinterUtil.SendContents(conn, "^FO40,235^A2,28,15^FD" + "Mfg Id:" + Sys.PartNumberModel.ManufactureID + "^FS");
    PrinterUtil.SendContents(conn, "^FO300,235^A2,28,15^FD" + "Mod Id:" + Sys.PartNumberModel.ModelID + "^FS");
    PrinterUtil.SendContents(conn, "^FO40,265^A2,28,15^FD" + Global.End.ToShortDateString() + "^FS");
    PrinterUtil.SendContents(conn, "^FO300,265^A2,28,15^FD" + Global.End.ToLongTimeString() + "^FS");
    PrinterUtil.SendContents(conn, "^XZ");
   }