Swift iOS AudioKIt: Presenting modal view causes audio crackle

Question

We have an AudioKit-based app and we're noticing that presenting modal views is causing short bursts of crackling audio. This doesn't happen with any other UI interactions; only modal views. We present the view over the main screen, with cross-dissolve:

@objc func showPushRequest() {
    let push = self.storyboard?.instantiateViewController(withIdentifier: "push") as! PushNotificationViewController
    push.modalTransitionStyle = .crossDissolve
    push.modalPresentationStyle = .overFullScreen
    self.present(push, animated: true, completion: nil)
}

The app is running AudioKit 4.11.2 (for now—will update to 5 when we have time), and our Conductor class owns and configures the signal chain. The modal is presented from our main ViewController.

Is there anywhere in particular I could start looking to solve the problem? Or are there any special characteristics of modal view presentation I should know about that might explain the crackles?