Google Play 结算查询PurchasesAsync 在存在有效订阅时返回空订阅列表

问：

通过该方法进行查询时，Google Play 结算库会返回一个空的订阅列表，而实际上存在有效的订阅。从 queryPurchasesAsync 的文档中：queryPurchasesAsync

仅返回有效订阅和未使用的一次性购买。此方法使用 Google Play 商店应用的缓存，而不发起网络请求。

我尝试清空Play商店缓存，但仍然返回一个空列表。

我使用的是 Play 结算库 6.0.1。这是我的相关代码：

private BillingClient billingClient;
private final Set<Purchase> purchases;
boolean billingClientConnected;

public static BillingManager getInstance(Activity activity) {
    if (billingManager == null) {
        billingManager = new BillingManager(activity);
    }
    return billingManager;
}

public BillingManager(Activity activity) {
    productList = new ArrayList<>();
    purchases = new HashSet<>();
    init(activity);
}

private void init(Activity activity) {

    // Create the billing client.
    billingClient = BillingClient.newBuilder(activity)
            .setListener(purchasesUpdatedListener)
            .enablePendingPurchases()
            .build();

    startBillingClientConnection();
}

public void startBillingClientConnection() {
    if (billingClient != null) {
        billingClient.startConnection(new BillingClientStateListener() {
            @Override
            public void onBillingSetupFinished(@NonNull BillingResult billingResult) {
                if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                    billingClientConnected = true;
                    // Do some other stuff..
                }
            }

            @Override
            public void onBillingServiceDisconnected() {
                // Try to restart the connection on the next request to
                // Google Play by calling the startConnection() method.
                billingClientConnected = false;
            }
        });
    }
}

public void queryPurchases() {
    if (!billingClientConnected) {
        startBillingClientConnection();
    } else {
        QueryPurchasesParams subsPurchasesParams = QueryPurchasesParams.newBuilder()
                .setProductType(BillingClient.ProductType.SUBS)
                .build();
        billingClient.queryPurchasesAsync(subsPurchasesParams, 
            new PurchasesResponseListener() {
                @Override
                public void onQueryPurchasesResponse(@NonNull BillingResult billingResult,
                                                 @NonNull List<Purchase> purchaseList) {
                    if (billingResult.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                        // Here I get an empty list.                    
                        // Handle all purchases that were successfully queried.
                        for (Purchase purchase : purchaseList) {
                            handlePurchase(purchase);
                        }
                    }
                }
            });
    }
}