Frequent FaultExceptions?

Can someone provide a bit more insight about what exactly causes Azure Service Bus to return FaultExceptions?

These have started happening pretty frequently for us (every few minutes) and I'm struggling to figure out why.  Due to the lack of detail in the messaging, it's completely unclear if (a) our code is doing something incorrectly to provoke this, (b) Service Bus is just unreliable, or (c) something else entirely.  They're happening frequently enough that it's worrisome to me and I'd really like to pin down the root cause so that we can attempt to prevent this from happening.

As a frame of reference, for the period from 10AM to 11AM yesterday, the management portal lists 16,756 "Total Requests" and 2,849 "Total Messages" (not really sure what exactly those numbers mean).  That equates to 4.5 requests/sec and less than 1 message/sec.  Given that's an hourly average, I'm sure that there are spikes higher than that, but given the guidance I've read, those numbers look _well_ below the threshold of what the Service Bus is supposed to be able to handle without even breaking a sweat.

Note that we're using the V2.3.0.0 of the SDK, which I believe by default uses an internal IRetryPolicy to retry failed requests, so I'm guessing that there are actually more errors than this and the only exceptions bubbling up are from the retry policy failing.  Here is the (utterly unhelpful) text of the exceptions (note that the lowest frame on the stack varies -- sometime's it's SetState, sometimes it's Send, sometimes its AcceptMessageSession, etc).

Microsoft.ServiceBus.Messaging.MessagingException: The server was unable to process the request; please retry the operation. If the problem persists, please contact your Service Bus administrator and provide the tracking id..TrackingId:c9e3a56f-6b48-4153-8e4d-dbecb04c7d14_G26_B3,TimeStamp:9/12/2014 5:52:47 PM ---> System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: The server was unable to process the request; please retry the operation. If the problem persists, please contact your Service Bus administrator and provide the tracking id..TrackingId:c9e3a56f-6b48-4153-8e4d-dbecb04c7d14_G26_B3,TimeStamp:9/12/2014 5:52:47 PM

Server stack trace:
   at Microsoft.ServiceBus.Messaging.Sbmp.DuplexRequestBindingElement.DuplexRequestSessionChannel.ThrowIfFaultMessage(MessagewcfMessage)
   at Microsoft.ServiceBus.Messaging.Sbmp.DuplexRequestBindingElement.DuplexRequestSessionChannel.HandleMessageReceived(IAsyncResultresult)

Exception rethrown at [0]:
   at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Sbmp.DuplexRequestBindingElement.DuplexRequestSessionChannel.DuplexCorrelationAsyncResult.End(IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Channels.ReconnectBindingElement.ReconnectChannelFactory`1.RequestSessionChannel.RequestAsyncResult.<GetAsyncSteps>b__4(RequestAsyncResultthisPtr, IAsyncResultr)
   at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.StepCallback(IAsyncResultresult)

Exception rethrown at [1]:
   at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Channels.ReconnectBindingElement.ReconnectChannelFactory`1.RequestSessionChannel.EndRequest(IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Sbmp.RedirectBindingElement.RedirectContainerChannelFactory`1.RedirectContainerSessionChannel.RequestAsyncResult.<>c__DisplayClass17.<GetAsyncSteps>b__a(RequestAsyncResultthisPtr, IAsyncResultr)
   at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.StepCallback(IAsyncResultresult)

Exception rethrown at [2]:
   at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Sbmp.RedirectBindingElement.RedirectContainerChannelFactory`1.RedirectContainerSessionChannel.EndRequest(IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Channels.ReconnectBindingElement.ReconnectChannelFactory`1.RequestSessionChannel.RequestAsyncResult.<GetAsyncSteps>b__4(RequestAsyncResultthisPtr, IAsyncResultr)
   at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.StepCallback(IAsyncResultresult)

Exception rethrown at [3]:
   at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Channels.ReconnectBindingElement.ReconnectChannelFactory`1.RequestSessionChannel.EndRequest(IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Sbmp.SbmpTransactionalAsyncResult`1.<GetAsyncSteps>b__3b(TIteratorAsyncResultthisPtr, IAsyncResulta)
   at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.StepCallback(IAsyncResultresult)

Exception rethrown at [4]:
   at Microsoft.ServiceBus.Common.AsyncResult.End[TAsyncResult](IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.Sbmp.SbmpMessageSession.OnEndSetState(IAsyncResultresult)
   at Microsoft.ServiceBus.Messaging.IteratorAsyncResult`1.StepCallback(IAsyncResultresult)
   --- End of inner exception stack trace ---

Server stack trace:


Exception rethrown at [0]:
   at Microsoft.ServiceBus.Messaging.MessageSession.SetState(Streamstream)