I am seeing a regression with XCUIDevice.shared.appearance = .dark in UI tests that only affects xcodebuild, not Xcode’s UI test runner. Setup • UI tests written using XCTest • Dark mode forced in setUp() using: XCUIDevice.shared.appearance = .dark • Tests target an iOS simulator • Same test target, same scheme Expected behavior The app launches in Dark Mode for UI tests, as it did previously. Actual behavior • When running UI tests from Xcode (Product > Test), Dark Mode is applied correctly. • When running the same UI tests via xcodebuild test, Dark Mode is ignored and the app launches in Light Mode. • No test failures, no warnings, no logs indicating the appearance override was skipped. Regression details • This used to work on older iOS versions when running via xcodebuild. • The regression appears after updating iOS simulators (exact version boundary still unclear). • No relevant changes were made to the test code, scheme, or CI configuration. • xcodebuild otherwise launches and runs UI tests normally. Notes • The issue is specific to XCUIDevice.shared.appearance. • Other UI test functionality behaves as expected. • This makes CI results inconsistent with local Xcode runs and breaks visual assumptions in snapshot and layout-based tests. Question Is this a known regression or an intentional behavior change in recent iOS / Xcode versions? If intentional, what is the supported way to reliably force Dark Mode in UI tests when running via xcodebuild? This currently makes xcodebuild-based CI UI testing unreliable compared to Xcode’s test runner.