Yes, I have the same problem using #Preview. No idea, why - and other sources (there are really few currently) did not help me on. Xcode Version 15.0 beta 8 (15A5229m).

Is it possible that the relationship MUST be an optional?

Well, the error occurred again between Parent and DateSpec. So, the workaround did not help. It seems that the relationship itself raises the problem.

Nearly the same problem here, just saying "not configured for the build action". Everything is set up as required, but xcodebuild throws an error, reproducibly on local as well as on Xcode Cloud. I have no clue how to proceed to get more details about the reason for the error. Xcode Version 14.0 beta (14A5228q). XX01 git:(develop) /Applications/Xcode-beta.app/Contents/Developer/usr/bin/xcodebuild -resolvePackageDependencies -workspace ./XX-Workspace.xcworkspace -scheme ***.v3 -derivedDataPath ./DerivedData -verbose                                                       git:(develop|)  2022-06-16 08:35:57.930 xcodebuild[4780:8362340] [MT] DVTSDK: Warning: SDK path collision for path '<DVTFilePath:0x600002d3c850:'/Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX13.sdk'>': SDK with name 'macosx13.0' being superseded by SDK with 'macosx13.0'. Command line invocation: /Applications/Xcode-beta.app/Contents/Developer/usr/bin/xcodebuild -resolvePackageDependencies -workspace ./XX-Workspace.xcworkspace -scheme ***.v3 -derivedDataPath ./DerivedData -verbose User defaults from command line: IDEDerivedDataPathOverride = /Users/***/Development/analyse/XX01/DerivedData IDEPackageSupportUseBuiltinSCM = YES 2022-06-16 08:35:58.405 xcodebuild[4780:8362370] nil host used in call to allowsSpecificHTTPSCertificateForHost 2022-06-16 08:35:58.405 xcodebuild[4780:8362370] nil host used in call to allowsAnyHTTPSCertificateForHost: Resolve Package Graph Resolved source packages:   swift-collections: https://github.com/apple/swift-collections @ 1.0.2   SwiftDate: https://github.com/malcommac/SwiftDate.git @ master   xctest-dynamic-overlay: https://github.com/pointfreeco/xctest-dynamic-overlay @ 0.2.1   combine-schedulers: https://github.com/pointfreeco/combine-schedulers @ 0.5.3   swift-identified-collections: https://github.com/pointfreeco/swift-identified-collections @ 0.4.0   swift-composable-architecture: https://github.com/pointfreeco/swift-composable-architecture.git @ main   swift-custom-dump: https://github.com/pointfreeco/swift-custom-dump @ 0.5.0   swift-case-paths: https://github.com/pointfreeco/swift-case-paths @ 0.9.0 2022-06-16 08:35:58.920 xcodebuild[4780:8362340] Writing error result bundle to /var/folders/wy/8nsfjsyn51zgcdhmc36wjjmdls2q5t/T/ResultBundle_2022-16-06_08-35-0058.xcresult xcodebuild: error: Scheme ***.v3 is not currently configured for the build action.

Thanks, GuiDev, this fixed the problem for me.