Windows Store App and Notification Hub - Windows Store registration is being deleted on Send

I use Notification Hubs to send Notifications to IPhone and Windows Store app. The IPhone is working perfectly fine, but there is some issue with Windows Store when sending the notification.

Template:

String WindowsTemplateStr = @"<toast><visual><binding template=""ToastImageAndText03""><image id=""1"" src=""https://"" alt=""Customer""/><text id=""1"">$(headlineText)</text><text id=""2"">$(bodyText)</text></binding></visual></toast>";

I use this code to register:

registration = await hubClient.CreateWindowsTemplateRegistrationAsync(userDeviceInformation.ChannelUri, Templates.WindowsNotificationTemplate,
                                new string[] 
                                        { 
                                            userDeviceInformation.InstallationId,
                                            userDeviceInformation.UserName 
                                        });

The registration goes through fine and I can see the tags properly associated using "Service Bus Explorer".

When I try to send the Notification this is what I do:

                        notification.Add("src", ImageUrl);

                    notification.Add("headlineText", String.Format("Message from {0}", fullName));
                    notification.Add("bodyText", String.Format("Message {0}", message));

When the notification is sent, nothing is received on the device; and I see the registration is also being deleted.

I can't seem to find what is causing this behavior.

Any ideas ?