Displaying to-many relationships in CoreData

Any CoreData experts know what could be going on here when trying to display to-many entity type relationship data?

On initialisation my model does an fetch request for an entity called Expense, and some prefetching for related entities (to-many type) like this: request.relationshipKeyPathsForPrefetching = ["splits"]

I was under the impression that calling a property on one of the related entities should fire the fault (if there is one) and give me the value. Here’s where it starts to go wrong. I have a property in my extension that I use in my detailed view:

public var viewExpenseSplits: [ExpenseSplit] {
    return splits?.allObjects as? [ExpenseSplit] ?? []
}

and then a list in my detail view:

List(expense.viewExpenseSplits, id: \.self) { split in
    Text(split.amount ?? "")
}

Result:

What's even more baffling is that I have no problem viewing these splits in the parent view. I thought perhaps I would have more luck passing the viewExpenseSplits through to the detail view instead of trying to access them from the Expense entity itself. Whilst I can print the data out when the view loads, my list still has the same problem.

I thought this would be trivial. Can anyone point to me where I'm going wrong?

Thanks!