IoT Hub Device twin returning connectionState = Disconnected, when it's actually connected

I have a Monitoring web job that querys my iot devices for any that have a connection state = disconnected, and then sends an email out to the user of that device to let them know it has a connection state issue.  I'm seeing a problem where one device will look like it is down about once every hour (or 1 hour and 5 minutes).  But the device is not down and there is no intermittent connection issue.  I currently have 3 devices, all connected through different internet ISPs.  One system started having this issue every so often, then another did, and now the 3rd one is having this issue.

My web job code is pretty simple and runs every 5 minutes to see if there are any devices that are down.  Here's my code

 public static async Task CheckDeviceAvailability([TimerTrigger("00:05:00", RunOnStartup = true)] TimerInfo timer)
        {
            string connectionString = CloudConfigurationManager.GetSetting("IotHubConnectionString");
            try
            {
                RegistryManager manager = RegistryManager.CreateFromConnectionString(connectionString);
                IQuery query = manager.CreateQuery("SELECT * FROM devices where ConnectionState = 'Disconnected'", 10);
                while (query.HasMoreResults)
                {
                    var page = await query.GetNextAsTwinAsync();
                    foreach (Twin twin in page)
                    {
                            await SendNotification(twin.DeviceId);
                    }
                }
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc.Message);
            }
        }

I've just added a check (if (twin.ConnectionState == DeviceConnectionState.Disconnected)) above the Await SendNotification line in the above code just to see if this helps out, but it seems like the query shouldn't be returning any devices that are connected.