AudioUnitRender error -50 with odd length buffers

I have a RemoteIO unit configured with AVAudioSessionCategoryPlayAndRecord. I find some strange behavior in it. I open the app, and immediately close it before audioUnit initializes fully (it actually initializes in background as I quit the app too soon). Next I bring the app to foreground and immediately on relaunch, I see AudioUnitRender failing with error -50 continuously. I find inNumberFrames to be 1115 and it fails whenever this number is odd.

  func recordingCallback(inRefCon:UnsafeMutableRawPointer,
                ioActionFlags:UnsafeMutablePointer<AudioUnitRenderActionFlags>,
                inTimeStamp:UnsafePointer<AudioTimeStamp>,
                inBusNumber:UInt32,
                inNumberFrames:UInt32,
                ioData:UnsafeMutablePointer<AudioBufferList>?) -> OSStatus
  {
       let controller = unsafeBitCast(inRefCon, to: MicrophoneOutput.self) 

      let listPtr = controller.audioBufferList.unsafeMutablePointer

     let buffers = UnsafeBufferPointer<AudioBuffer>(start: &listPtr.pointee.mBuffers, count: Int(listPtr.pointee.mNumberBuffers))

   for var buf in buffers {
       buf.mDataByteSize = inNumberFrames * UInt32(sampleWordSize)
    }

   let status = AudioUnitRender(controller.audioUnit!, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, listPtr)

if noErr != status {
   print("Error \(status)");
   NSLog("\(AVAudioSession.sharedInstance().currentRoute.inputs[0])")
   fatalError("Render status \(status)")
  // return status;
}

return noErr

}

Strangely, if I hardcode inNumberFrames to be 1114 in AudioUnitRender call, it succeeds! Does anyone know what is going on? The pattern is as soon as the app resumes from background, there is a route change notification, and then the first sample in callback is of length 1114 frames but the one next to it has 1115 frames which fails.

It turned out it was a programming error due to misunderstandings in Swift language. The line that was culprit was this:

for var buf in buffers {
   buf.mDataByteSize = inNumberFrames * UInt32(sampleWordSize)
}

This answer provides more detail - Swift vs Objective C pointer manipulation issue