CoreData's automaticallyMergesChangesFromParent causes SwiftUI view to update twice

I have the following CoreData stack in my app:

let mom = NSManagedObjectModel(contentsOf:modelURL)!
managedObjectContext = NSManagedObjectContext(concurrencyType:.mainQueueConcurrencyType)
privateContext = NSManagedObjectContext(concurrencyType:.privateQueueConcurrencyType)
coordinator = NSPersistentStoreCoordinator(managedObjectModel:mom)
managedObjectContext.automaticallyMergesChangesFromParent = true
privateContext.automaticallyMergesChangesFromParent = true
privateContext.persistentStoreCoordinator = coordinator
managedObjectContext.parent = privateContext
managedObjectContext.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType)
privateContext.mergePolicy = NSMergePolicy(merge: .mergeByPropertyObjectTrumpMergePolicyType)

So, managedObjectContext is what I use for Main Actor's reads/writes, while the privateContext is responsible for heavy lifting – writing/reading from SQL store itself.

When I need to save data, I use the following method:

func save() {
    if !(managedObjectContext.hasChanges) {
        return
    }
    do {
        try self.managedObjectContext.safeSave()
        do {
            try self.privateContext.safeSave()
        }
        catch let error {
            // HANDLE ERROR
        }
    }
    catch let error as NSError {
        // HANDLE ERROR
    }
}

// .....

extension NSManagedObjectContext {
    func safeSave() throws {
        try performAndWait {
            if hasChanges {
                try save()
            }
        }
    }
}

The problem that I encounter is that whenever I save an entity, any SwiftUI view which observes it gets updated twice. And the reason for a second update is that due to automaticallyMergesChangesFromParent set to true, the second update is when an entity turns into a fault.

This is extremely confusing and I do not understand why this occurs. For example:

struct CellView: View {
    @ObservedObject private var topic: TopicStatistic

    var body: some View {
        print("CELL BODY \(topic)")
        return Button {
            topic.isSelected = !topic.isSelected
            DataStack.shared.save() //calls save method illustrated above
        } label: { Text("Test") }
    }
}

This prints two "CELL BODY" whenever I tap on the button, the first one is:

CELL BODY <Topic: 0x600002137b60> (entity: Topic; id: 0x85da4595cd988912 <x-coredata://F05EF0BE-58F4-423C-A12E-E4FF67BE17D5/Topic/p65>; data: {
    isSelected = 0;
    // other properties here
})

The second one is:

CELL BODY <Topic: 0x60000213dc20> (entity: Topic; id: 0x8db98711ee4d8ece <x-coredata://F05EF0BE-58F4-423C-A12E-E4FF67BE17D5/Topic/p53>; data: <fault>)

As you can see, the second update is when Topic turns into a fault.

What I have verified:

1. Removing any one of automaticallyMergesChangesFromParent removes this issue
2. If I do not use the "middle" privateContext and attach managedObjectContext directly to the persistent store, the issue also resolves.

However, none if these are good options for me. I have another background context which is used for Cloud sync, so I do want to both keep this setup and to ensure that changes are propagated.

Does anyone know why objects turn into faults when I would assume that changes go one way to the persistent store when I click on a button?