iOS Intermittent Bug: UserDefaults Preferences Loading Issue Problem Summary We're experiencing an intermittent issue where UserPreferences.shared.preferences returns inconsistent values even after calling getPreferences(). The behavior is unpredictable and affects critical functionality. Environment iOS Version: 15+ Language: Objective-C with Swift interop Storage: UserDefaults with App Group (group.com.jci.tyco.glss) Architecture: Singleton pattern for UserPreferences (Swift class) The Issue When a push notification arrives and triggers the showEvent: method, user preferences are sometimes loaded correctly and sometimes return nil or default values: Scenario A (Works - ~60% of time): Scenario B (Fails - ~40% of time): Observed Pattern From extensive logging over multiple test runs: Key Observation: At app launch: Preferences often load successfully Seconds later when push arrives: Same preferences become unavailable User navigates to another screen and back: Preferences suddenly work again Code Structure Objective-C AppDelegate.m - (void)showEvent:(FMEvent *)event eventReadSource:(FMEventReadSourceType)eventSource { BOOL isUserRoleEndUser = [[FMUserRolesRepository instance] userRoleAvailable:FMUserRoleEndUser]; UserPreferences *userPrefs = [UserPreferences shared]; [userPrefs getPreferences]; // ← Called here // Immediately after, sometimes nil! bool hasFireAudio = [userPrefs.preferences.fireAudio.lowercaseString isEqual:@"true"]; NSLog(@"isUserRoleEndUser: %d | Fire Audio: %d", isUserRoleEndUser, hasFireAudio); // Decision logic based on preferences if ([FMConstants getUserRegion] == UserRegionUK && isUserRoleEndUser && userPrefs.preferences && // ← Sometimes nil here hasFireAudio) { // Show Screen A } else { // Show Screen B } } ```class UserPreferences: NSObject { static let shared = UserPreferences() var preferences: FMUserPreferencesInfo? // ← This becomes nil intermittently func getPreferences() { let userDefaults = UserDefaults(suiteName: "group.com.jci.tyco.glss") if let data = userDefaults?.data(forKey: "UserPreferences") { // Decode and set preferences self.preferences = // decoded object } else { // Create default preferences with fireAudio = "false" self.preferences = FMUserPreferencesInfo() } } }