AKAmplitudeEnvelope is not working, just bypass the signal

Im trying to use AKAmplitudeEnvelope in the project, and it gives zero ADSR shaping. I wrote simple code to check this - the same result:

import Foundation
import AudioKit

class ViewController: UIViewController {

    lazy var osc = AKOscillator(waveform: AKTable(.sine), frequency: 150, amplitude: 1)
    lazy var envelope = AKAmplitudeEnvelope(osc)    
    
    override func viewDidLoad() {
        super.viewDidLoad()
    
        envelope.attackDuration = 0.01
        envelope.decayDuration = 0.2
        envelope.sustainLevel = 0.5
        envelope.releaseDuration = 0.5
        
        AudioKit.output = envelope
        
        do {
            try AudioKit.start()
        } catch {
            print(error)
        }
        osc.start()
    }

    
    @IBAction func startPressed(_ sender: UIButton) {  //pressing the button
        
      envelope.stop()  
      envelope.start()
    }
}

So, when I press the button("startPressed" function) -just oscillator starting to sound permanently, without any ADSR amplitude forming