title: Unexpected Optimistic concurrency exception
body: <p>I try to update a field of my object, and save it right away to the database.</p>
  
  <pre><code>using (var ctx = new DataModel(_connectionString))
  {
      var MyObject it = ctx.MyObjects.Where(someConstraint).ToList()[0];
      try
      {
          //update check time
          ctx.Refresh(RefreshMode.StoreWins, it); //making sure I have it
          ctx.AcceptAllChanges(); // in case something else modified it - seems unnecessary
          it.TimeProperty= DateTime.UtcNow; //Setting the field
          ctx.DetectChanges(); //seems unnecessary
          ctx.SaveChanges(SaveOptions.AcceptAllChangesAfterSave); //no SaveOptions changed the behavior
      }
      catch (OptimisticConcurrencyException)
      {
          _logger.DebugFormat(workerClassName + ": another worker just updated the LastCheckTime");
      }
      //Do some other work and/or sleep
  }
  </code></pre>
  
  <p>When I run this in Azure emulator with 2 instances or more, I get a lot of OptimisticConcurrencyExceptions here.</p>
  
  <p>I am trying to refresh the object, update one of its fields, then push those changes to the database. 
  However, Optimistic Concurrency is preventing me.</p>
  
  <p>note: The optimistic concurrency is set on a TimeStamp field which I never touch.</p>
  
  <p>Why is that, and how can I fix it?</p>