Unrecognized selector objectAtIndex

Unrecognized selector objectAtIndex 2022-06-21 22:41:30.447763+0200 App[56115:1179524] -[__NSCFSet objectAtIndex:]: unrecognized selector sent to instance 0x600003df9c20 This happened with the following code, basically when trying to do a ForEach on a property coming from a CoreData model: import CoreData import SwiftUI struct BudgetView: View { @FetchRequest(entity: CategoryGroup.entity(), sortDescriptors: []) var categoryGroups: FetchedResults<CategoryGroup> var body: some View { VStack { List { ForEach(categoryGroups, id: .id) { group in Text(group.name) ForEach(group.categories, id: .id) { category in Text(category.