Flutter GridView ListTiles appear below scroll container - flutter

Question

I have a Flutter scrolling GridView builder that looks like it renders the ListTiles below the Container the GridView is placed in. It appears it renders placeholder grid list tiles even when they are not within the Container bounds.
It looks like for some reason that the GridView ListTiles appear outside (below) the parent container.
In this example the GridView is placed within a Container that is then placed as a child under a parent Scrollbar that is a child widget in a Column. The GridView appears to render the grid ListTiles (renders the background Tile color but not the Tile contents) outside its parent container, appearing as Tiles under the other child widgets of the parent Column widget. See screen grabs below.
Grid List tiles under the Container
When I scroll the list up the shadow Tiles appear in the GridView with the Tile contents.
When I scroll back the Tiles below the GridView appear below?/under? the other widgets in the parent Column. See first image the colored area under the "Bye" text widget.
`
import 'package:flutter/material.dart';
import 'package:scroll5/models/task_model.dart';
/// This is the stateful widget that the main application instantiates.
class ScrollListWidget extends StatefulWidget {
final List<TaskCard> _list;
ScrollListWidget({Key? key})
: _list = [],
super(key: key);
const ScrollListWidget.withList(
List<TaskCard> list, {
Key? key,
}) : _list = list,
super(key: key);
#override
State<ScrollListWidget> createState() => _ScrollListStatefulWidgetState();
}
/// This is the private State class that goes with MyStatefulWidget.
class _ScrollListStatefulWidgetState extends State<ScrollListWidget> {
#override
Widget build(BuildContext context) {
return Container(height: 240, child: GridView.builder(
shrinkWrap: true,
physics: ScrollPhysics(),
itemCount: widget._list.length,
itemBuilder: (context, index) => WordTile(
widget._list[index].taskName(), widget._list[index].daysEffort()),
gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
crossAxisCount: 2,
childAspectRatio: 4,
),
));
}
}
class WordTile extends StatelessWidget {
final String word;
final int score;
const WordTile(this.word, this.score, {super.key});
#override
Widget build(BuildContext context) {
return ListTile(
tileColor: Colors.green.withOpacity(.4), title: Text(word));
}
}`
GridView within a Container contained within a Scrollbar and Column
#override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child:
Column(children: [
Scrollbar(
controller: _scrollController,
thickness: 8,
interactive: true,
thumbVisibility: true,
child:ScrollListWidget.withList(_taskList)
),
Text("Bye",style: TextStyle())])),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add)));
// This trailing comma makes auto-formatting nicer for build methods.
}`