目前还没有官方的解决方法，但是可以考虑使用SFSafariViewController替代ASWebAuthenticationSession来解决这个问题。下面是一个示例代码：

let authURL = URL(string: "https://example.com/auth")!
let callbackURLScheme = "myapp"

let safariViewController = SFSafariViewController(url: authURL)
safariViewController.delegate = self

present(safariViewController, animated: true)

// SafariViewControllerDelegate callback methods
func safariViewController(_ controller: SFSafariViewController,
                          initialLoadDidRedirectTo URL: URL) {
    if URL.absoluteString.starts(with: "\(callbackURLScheme)://") {
        // Handle callback URL
    }
}

func safariViewControllerDidFinish(_ controller: SFSafariViewController) {
    // User dismissed the view controller without authenticating
}