[BUG] "flutter build windows" successful, but "Build files not found" -- library outdated? #308

PS E:\code\app> flutter build windows
CMake Warning (dev) at flutter/ephemeral/.plugin_symlinks/webview_win_floating/windows/CMakeLists.txt:42 (add_custom_command):
  The following keywords are not supported when using
  add_custom_command(TARGET): DEPENDS.

  Policy CMP0175 is not set: add_custom_command() rejects invalid arguments.
  Run "cmake --help-policy CMP0175" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.
This warning is for project developers.  Use -Wno-dev to suppress it.

Building Windows application...                                    75.6s
√ Built build\windows\x64\runner\Release\app.exe        <-- SUCCESSFUL!!! NOTICE "x64" IN PATH
PS E:\code\app> dart run msix:create 
Building package executable... 
Built msix:create.
running "flutter build windows"...     25.5s            <-- RUNNING IT AGAIN FOR SANITY CHECK
creating msix installer...             /Unhandled exception:
Build files not found at E:\code\app/build/windows/runner/Release, first run "flutter build windows" then try again <-- WHY NO "x64"?
#0      Configuration.validateBuildFiles (package:msix/src/configuration.dart:245:7)
<asynchronous suspension>
#1      Msix._createMsix (package:msix/msix.dart:79:5)
<asynchronous suspension>
#2      Msix.create (package:msix/msix.dart:33:5)
<asynchronous suspension>
#3      main (file:///C:/Users/t/AppData/Local/Pub/Cache/hosted/pub.dev/msix-3.4.1/bin/create.dart:4:3)
<asynchronous suspension>

name: app
description: "My app."
publish_to: 'none'
version: 1.0.0+1
environment:
  sdk: ^3.8.1

dependencies:
  auto_route: ^10.1.0+1
  dio: ^5.8.0+1
  flutter_mobx: ^2.3.0
  get_it: ^8.0.3
  intl: any
  json_annotation: ^4.9.0
  logger: ^2.6.0
  mobx: ^2.5.0
  qr_flutter: ^4.1.0
  retrofit: ^4.6.0
  web_socket_channel: ^3.0.3
  webview_flutter: ^4.13.0
  webview_win_floating: ^2.3.1
  window_manager: ^0.5.1
  flutter:
    sdk: flutter
  flutter_localizations:
    sdk: flutter
  cupertino_icons: ^1.0.8

dev_dependencies:
  auto_route_generator: ^10.1.0+1
  build_runner: ^2.5.4
  json_serializable: ^6.9.5
  mobx_codegen: ^2.7.0
  msix: ^3.4.1
  retrofit_generator: ^9.6.0
  flutter_test:
    sdk: flutter
  flutter_lints: ^5.0.0

flutter:
  # https://docs.flutter.dev/ui/accessibility-and-internationalization/internationalization
  generate: true
  uses-material-design: true

msix_config:
  display_name: Kiosk Signage Dashboard
  msix_version: 1.0.0.0
  logo_path: E:\code\app\logo.png
  capabilities: "internetClientServer"