IQFundamental-no-longer-returns-NAICS-and-Common-Shares-Outstanding-for-some-tickers

Some IQFeed Fundamentals no longer work. Can you tell me if this is a DTN server problem or an IQFeed extension problem? The fundamentals affected are NAICS industry classification code and the Common shares outstanding count.

I'm running the IQFeed Build 28 extension and the IQFeed client 6.2.0.25 under WL8 B109. I'm still running WL6, so I prefer not to upgrade the IQFeed client.

The code below works for ticker RIOT, but not for tickers AAPL ADNT AMT DFIN FRO NTNX PCTY PEN PFBC PLYM SSYS VZ ZBRA. Why does it work for some ticker symbols and not others?

CODE:
using System;
using WealthLab.Backtest;
using WealthLab.Core;
using WealthLab.IQFeed; //* IQFeed IQFundamental class here *//

namespace WealthScript7 
{
   public class MyStrategy : UserStrategyBase
   {
      public override void Initialize(BarHistory bars)
      {
         int code = IQFundamental.ValueInt(bars.Symbol, "NAICS");
         WriteToDebugLog(string.Format("NAICS classification code:\t{0}\n", code));
         double sharesOutstanding = IQFundamental.ValueDouble(bars.Symbol, "Common shares outstanding") * 1000.0;
         WriteToDebugLog(string.Format("Common shrs:\t{0}", sharesOutstanding));
      }

      public override void Execute(BarHistory bars, int idx) { }
   }
}