AVMIDIPlayer leaks memory

I'm using AVMIDIPlayer to play a MIDI file in Swift on iOS. This works for a number of times. After I've played the file several times, notes starts muting, until nothing sounds at all.

This seems to be a memory leak. Memory usage of the application grows each time you play a MIDI file, and there is no way to free this memory. The larger the soundfont, the worst the problem.

I submitted a bug report a month ago on this and haven't received any answer. There is also a post on Stack Overflow by another user on this.

Is there any workaround to this issue?

Here is a test case where you can reproduce the issue:

import UIKit
import AVFoundation

class ViewController: UIViewController {

    var soundBank : NSURL!
    var midiPath : NSURL!
    var midi : AVMIDIPlayer!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.soundBank = NSBundle.mainBundle().URLForResource("soundfonts/TimGM6mb", withExtension: "sf2")
        self.midiPath = NSBundle.mainBundle().URLForResource("mozart", withExtension: "mid")
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    @IBAction func playMidi(sender: UIButton) {
        var error: NSError?
        do {
            self.midi = try AVMIDIPlayer(contentsOfURL: self.midiPath, soundBankURL: self.soundBank)
        } catch let error1 as NSError {
            error = error1
            self.midi = nil
        }  catch {
            NSLog("Exception creating AVMIDIPlayer")
        }
        if let e = error {
            NSLog("Error creating AVMidiPlayer: \(e.localizedDescription)")
            self.midi = nil
        } else {
            midi.prepareToPlay()
            self.midi.play(nil)
        }
    }

}