Why does this Combine subscription not cause a retain cycle?

Question

I noticed this was triggering the deinit block even without weak/unowned used. I simplified the code to show what is happening.

final class ViewModel: ObservableObject {
    @Published var isLoading = false
    private var cancellables: [AnyCancellable] = []

    var randomPublisher: AnyPublisher<Void, Never> {
        Just(()).eraseToAnyPublisher()
    }

    func someAction() {
        randomPublisher.sink { completion in
            self.isLoading = false                
            switch completion {
                case .finished:
                break
            }
        } receiveValue: { _ in  }
        .store(in: &cancellables)
    }
}

struct SampleView: View {
    @StateObject private var viewModel = ViewModel()
}

I would think there is a reference cycle when someAction() is called as self is captured inside the subscription and the viewmodel holds the subscription array. It's successfully accessing the deinit block when view is dismissed so why is that the case whereas in other viewmodels I need to make self weak in the same place?