i have done some things to solve this thing, may be you have better solution 。please check it when you have the time.
i notice outerscrollcontrol will handle the pinned scroll extend, so i done some to fix it.
https://github.com/fluttercandies/extended_nested_scroll_view

Any progress on this issue? This should be fixed in the flutter itself as well

It’s already in the second half of 2019, and I still haven’t seen any progress on this issue. T_T

@vanlooverenkoen I don't understand why this ticket was closed. This ticket is definitely not addressed as of today.
Flutter provides no solution to absorb the height of more than one child. This limits design abilities as no fixed size element can be used between the AppBar and the scrolling content of a child.

I am still having this issue, it is not yet resolved from flutter

This code support double sliver pinned appbar without the issue where small body go behind second app bar.

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: Home(),
    ),
  );
}

class Home extends StatelessWidget {
  Home({super.key});

  final SliverOverlapAbsorberHandle appBar = SliverOverlapAbsorberHandle();
  final SliverOverlapAbsorberHandle disconnectBar =
      SliverOverlapAbsorberHandle();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: NestedScrollView(
        physics: const ClampingScrollPhysics(),
        headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) =>
            <Widget>[
          SliverOverlapAbsorber(
            handle: appBar,
            sliver: const SliverAppBar(
              pinned: true,
              backgroundColor: Colors.red,
              elevation: 0,
              toolbarHeight: 50,
              expandedHeight: 100,
              title: Center(
                child: Text("First pinned appbar"),
              ),
            ),
          ),
          SliverOverlapAbsorber(
            handle: disconnectBar,
            sliver: const SliverAppBar(
              pinned: true,
              backgroundColor: Colors.green,
              elevation: 0,
              primary: false,
              toolbarHeight: 20,
              expandedHeight: 100,
              title: Center(
                child: Text("Second pinned appbar"),
              ),
            ),
          ),
        ],
        body: Builder(
          builder: (BuildContext context) => CustomScrollView(
            slivers: <Widget>[
              SliverOverlapInjector(handle: appBar),
              SliverOverlapInjector(handle: disconnectBar),
              SliverToBoxAdapter(
                child: Container(
                  color: Colors.grey,
                  height: 100,
                  width: double.infinity,
                  child: const Center(child: Text("body")),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

worked out fine for me!! thanks!!

#22393 (comment)

The solution presented here doesn't work properly when you have a CustomScrollView in the body of your NestedScrollView, only the MultiSliver seems to do the work.

#22393 (comment)

It works for my case.
headerSliverBuilder of NestedScrollView has one floating appbar, one pinned appbar

and body has CustomScrollview, it has 2 SliverOverlapInjector.

It works properly even with CustomScrollView in the body of NestedScrollView

Resolving #33137 (currently in progress) will resolve this as well since multiple slivers will be able to go into the group, and the group itself will be able to go into the SliverOverlapAbsorber. 👍

This has been resolved by #126596. With SliverMainAxisGroup, multiple slivers can be wrapped by the group, and then the group can be provided to the SliverOverlapAbsorber. :) cc @thkim1011

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.