Some of our users on iOS 17.5+ started to encounter crash due to: SwiftData/BackingData.swift:669: Fatal error: Unknown Relationship Key - subscription) We have tried using SwiftData on the MainActor only but an issues still effects some of our users. Our models look like these: @Model public final class ProfileModel { public static let fetchDescriptor = FetchDescriptor<ProfileModel>.self public enum Gender: Codable { case female case male case other } public enum Units: Codable { case imperial case metric } public enum Eating: Codable { case empath case enthusiast case explorer case guardian case harmonizer case pacifier case regulator case stoic case iosDefault } public enum RegistrationSource: Codable { case iOS case web } public enum NHE: Codable { case combined case emotional case mindless } public enum Goal: Codable { case beHealthier case energyIncrease case healthyHabits case looseWeight case relationshipsWithFood } public enum WeightLossFocus: Codable { case activity case healthyHabits case nutrition case other } @Attribute(.unique) public let id: String public let isPaid: Bool public let eating: Eating public let registrationSource: RegistrationSource public let nhe: NHE? public let firstName: String? public let lastName: String? public let gender: Gender? public let height: String? public let age: Int? public let weight: String? public let targetWeight: String? public let bmi: String? public let goal: Goal? public let units: Units? public let weightLossFocus: WeightLossFocus? @Relationship(deleteRule: .cascade) public var subscription: ProfileSubscriptionModel? public init( id: String, isPaid: Bool, eating: Eating, registrationSource: RegistrationSource, nhe: NHE?, firstName: String?, lastName: String?, gender: Gender?, height: String?, age: Int?, weight: String?, targetWeight: String?, bmi: String?, goal: Goal?, units: Units?, weightLossFocus: WeightLossFocus?, subscription: ProfileSubscriptionModel? ) { self.id = id self.isPaid = isPaid self.eating = eating self.registrationSource = registrationSource self.nhe = nhe self.firstName = firstName self.lastName = lastName self.gender = gender self.height = height self.age = age self.weight = weight self.targetWeight = targetWeight self.bmi = bmi self.goal = goal self.units = units self.weightLossFocus = weightLossFocus self.subscription = subscription } } @Model public final class ProfileSubscriptionModel { public static let fetchDescriptor = FetchDescriptor<ProfileSubscriptionModel>.self public let price: Double public let currency: String public let period: Int public let status: String public let expirationDate: Date public let cancelledAt: Date? public init(price: Double, currency: String, period: Int, status: String, expirationDate: Date, cancelledAt: Date?) { self.price = price self.currency = currency self.period = period self.status = status self.expirationDate = expirationDate self.cancelledAt = cancelledAt } }