flutter portal bug

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_portal/flutter_portal.dart';

void main() {
  runApp(const App());
}

class App extends StatefulWidget {
  const App({super.key});

  @override
  State<App> createState() => _AppState();
}

class _AppState extends State<App> {
  @override
  Widget build(BuildContext context) {
    return Portal(
      child: MaterialApp(
        home: PortalTarget(
          visible: true,
          portalFollower: const Align(
            alignment: Alignment.bottomCenter,
            child: A(),
          ),
          child: Builder(
            builder: (context) {
              return Scaffold(
                body: Center(
                  child: ElevatedButton(
                    onPressed: () {
                      Navigator.of(context).push(MaterialPageRoute(
                        builder: (context) =>
                            Scaffold(body: Center(child: Text('2'))),
                      ));
                    },
                    child: Text('push'),
                  ),
                ),
              );
            },
          ),
        ),
      ),
    );
  }
}

class A extends StatefulWidget {
  const A({super.key});

  @override
  State<A> createState() => _AState();
}

class _AState extends State<A> {
  bool _toggle = false;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () => setState(() {
        _toggle = !_toggle;
        Future.delayed(const Duration(seconds: 1), () {
          setState(() => _toggle = false);
        });
      }),
      child: Container(
        width: 200,
        height: 200,
        color: Colors.black,
        alignment: Alignment.center,
        child: AnimatedOpacity(
          duration: const Duration(seconds: 1),
          opacity: _toggle ? 1 : 0,
          child: const Text('A'),
        ),
      ),
    );
  }
}