In large apps with feature flags, did dark mode ever create versioning problems?

When feature flags are used to roll out UI changes incrementally, dark mode support can break inconsistently across an app. A real-world case shows how a flagged feature used new semantic color tokens while older screens still used hardcoded colors, causing half the app to adapt to dark mode and half not to. The fix involved auditing and standardizing color tokens across all modules, with a lesson learned about needing a migration plan before rolling out appearance refactors behind flags.