iOS Build Fails with "Scheme Runner not found" Error

[CeferinSoftware]

If you are looking for help, please confirm the following...

• I confirm I have searched the Docs, Codemagic Sample Projects, and GitHub Discussions.
• I confirm the software versions on my local computer match the ones in CI environment (e.g. Xcode version, Gradle version). See here
• I confirm I am able to do a fresh clone of the repository and build the project on my local computer.

Which mobile framework are you using?

Flutter (Dart)

Steps to reproduce

Create a Flutter project with iOS platform
Configure Codemagic to build the iOS app using Workflow Editor
Set up code signing with Automatic method, Bundle ID: Automatic, Profile type: App Store
Set environment variables:
XCODE_WORKSPACE=ios/Runner.xcworkspace
XCODE_SCHEME=Runner
CM_FLUTTER_SCHEME=Runner
Set build arguments to: --release
Start the build process

Expected results

The iOS build should complete successfully, generating a signed IPA file that can be uploaded to App Store Connect.

Actual results

The build fails with the error message:

Build failed :|
Scheme "Runner" not found from repository! Please reconfigure your project.

Despite the Runner.xcscheme file existing in ios/Runner.xcodeproj/xcshareddata/xcschemes/, and all configuration appearing correct, Codemagic cannot locate or recognize the scheme.

Build id (optional)