Different behavior of a Flutter Stack() widget on different locations

I’m working a floating action button with some twists: when you click on the FloatingActionButton(), some InkWell() widgets become visible from a Stack(), where you can click on multiple options. When I inserted it to my application, I experienced something weird:

If I add the unique MyFAB() widget as a "home" option within MaterialApp(), the animation works perfectly and you can click on the small InkWell() widgets without any problems:

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home:  MyFAB(),
    );
  }
}

class MyFAB extends StatefulWidget {
  const MyFAB({Key? key}) : super(key: key);

  @override
  State<MyFAB> createState() => _MyFABState();
}

class _MyFABState extends State<MyFAB> with SingleTickerProviderStateMixin {
  late AnimationController _animationController;
  late Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _animationController = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 300),
    );

    _animation = CurvedAnimation(
      parent: _animationController,
      curve: Curves.easeInOut,
    );
  }

  @override
  void dispose() {
    _animationController.dispose();
    super.dispose();
  }

  void _toggle() {
    if (_animationController.isDismissed) {
      _animationController.forward();
    } else {
      _animationController.reverse();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      alignment: Alignment.center,
      children: [
        _buildOption(Icons.mood, -0.2),
        _buildOption(Icons.sentiment_satisfied, 0.27),
        _buildOption(Icons.sentiment_dissatisfied, 0.72),
        _buildOption(Icons.mood_bad, 1.2),
        FloatingActionButton(
          heroTag: "MyFAB",
          onPressed: _toggle,
          shape: const CircleBorder(),
          child: AnimatedIcon(
            icon: AnimatedIcons.menu_close,
            progress: _animation,
          ),
        ),
      ],
    );
  }

  Widget _buildOption(IconData icon, double index) {
    final double angle = (index - 1.5) * 0.5 * pi;
    return AnimatedBuilder(
      animation: _animation,
      builder: (context, child) {
        final double offsetX = _animation.value * 70 * cos(angle);
        final double offsetY = _animation.value * 70 * sin(angle);
        return Transform.translate(
          offset: Offset(offsetX, offsetY),
          child: Transform.scale(
            scale: _animation.value,
            child: Material(
              color: Colors.transparent,
              child: InkWell(
                onTap: () {
                  print('Option tapped');
                  _toggle();
                },
                borderRadius: BorderRadius.circular(20),
                splashColor: Colors.grey.withOpacity(0.5),
                child: CircleAvatar(
                  radius: 20,
                  child: Icon(icon),
                ),
              ),
            ),
          ),
        );
      },
    );
  }
}

But if I add MyFAB() into a Scaffold() as a "floatingActionButton", the small icons become useless, you cannot click on them anymore.

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        floatingActionButton: MyFAB(),
        floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      ),
    );
  }
}

class MyFAB extends StatefulWidget {
  const MyFAB({Key? key}) : super(key: key);

  @override
  State<MyFAB> createState() => _MyFABState();
}

class _MyFABState extends State<MyFAB> with SingleTickerProviderStateMixin {
  late AnimationController _animationController;
  late Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _animationController = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 300),
    );

    _animation = CurvedAnimation(
      parent: _animationController,
      curve: Curves.easeInOut,
    );
  }

  @override
  void dispose() {
    _animationController.dispose();
    super.dispose();
  }

  void _toggle() {
    if (_animationController.isDismissed) {
      _animationController.forward();
    } else {
      _animationController.reverse();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      alignment: Alignment.center,
      children: [
        _buildOption(Icons.mood, -0.2),
        _buildOption(Icons.sentiment_satisfied, 0.27),
        _buildOption(Icons.sentiment_dissatisfied, 0.72),
        _buildOption(Icons.mood_bad, 1.2),
        FloatingActionButton(
          heroTag: "MyFAB",
          onPressed: _toggle,
          shape: const CircleBorder(),
          child: AnimatedIcon(
            icon: AnimatedIcons.menu_close,
            progress: _animation,
          ),
        ),
      ],
    );
  }

  Widget _buildOption(IconData icon, double index) {
    final double angle = (index - 1.5) * 0.5 * pi;
    return AnimatedBuilder(
      animation: _animation,
      builder: (context, child) {
        final double offsetX = _animation.value * 70 * cos(angle);
        final double offsetY = _animation.value * 70 * sin(angle);
        return Transform.translate(
          offset: Offset(offsetX, offsetY),
          child: Transform.scale(
            scale: _animation.value,
            child: Material(
              color: Colors.transparent,
              child: InkWell(
                onTap: () {
                  print('Option tapped');
                  _toggle();
                },
                borderRadius: BorderRadius.circular(20),
                splashColor: Colors.grey.withOpacity(0.5),
                child: CircleAvatar(
                  radius: 20,
                  child: Icon(icon),
                ),
              ),
            ),
          ),
        );
      },
    );
  }
}

I’m a self-taught Flutter developer, still pretty new to it, so I got stuck at this point. What causing this behavior? How can I use MyFAB() within the Scaffold() without any problems?

You can try out my codes in https://dartpad.dev/

Thanks in advance!

I recoded the entire MyFAB() not to use Stack() widget, removed the "floatingActionButtonLocation" option from the Scaffold(), nothing helped.