NullPointerException in PurchaseParams.Builder (Android: java)

This is the Crash Report I got from the Play Console: 

Type

java.lang.NullPointerException

Exception java.lang.NullPointerException:
  at com.revenuecat.purchases.PurchaseParams$Builder.<init> (PurchaseParams.kt)
  at com.xxxxxxxxxxxx.MainActivity.purchase (MainActivity.java:2103)
  at com.xxxxxxxxxxxx.MainActivity.lambda$showPaywall$33 (MainActivity.java:2014)
  at android.view.View.performClick (View.java:7792)
  at android.widget.TextView.performClick (TextView.java:16112)
  at android.view.View.performClickInternal (View.java:7769)
  at android.view.View.access$3800 (View.java:910)
  at android.view.View$PerformClick.run (View.java:30218)
  at android.os.Handler.handleCallback (Handler.java:938)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loopOnce (Looper.java:226)
  at android.os.Looper.loop (Looper.java:313)
  at android.app.ActivityThread.main (ActivityThread.java:8751)
  at java.lang.reflect.Method.invoke
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:571)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1135)

Here is my code:

    protected void purchase(Package purchasePackage) {
        Log.d(TAG_REVENUECAT, "RC: Purchases.getSharedInstance().purchase");
        Purchases.getSharedInstance().purchase(
            new PurchaseParams.Builder(this, purchasePackage).build(), new PurchaseCallback() {
                @Override
                public void onCompleted(@NonNull StoreTransaction storeTransaction, @NonNull CustomerInfo customerInfo) {
                    if (customerInfo.getEntitlements().get(PREMIUM_ENTITLEMENT_ID) != null) {
                        if (Objects.requireNonNull(customerInfo.getEntitlements().get(PREMIUM_ENTITLEMENT_ID)).isActive()) {
                            // Unlock that great "pro" content
                            Log.d(TAG_REVENUECAT, "RC: Purchase completed");
                            AlertDialog.Builder alertBuilder = new AlertDialog.Builder(MainActivity.this);
                            alertBuilder.setTitle(R.string.thankyou)
                                .setCancelable(false)
                                .setPositiveButton(android.R.string.ok, (dialog, id) -> {})
                                .show();
                            enablePremium(true);
                        }
                    }
                }
                @Override
                public void onError(@NonNull PurchasesError purchasesError, boolean userCancelled) {
                    // No purchase
                    Log.e(TAG_REVENUECAT, purchasesError.toString());
                    Log.d(TAG_REVENUECAT, "Purchase error");
                    if (!userCancelled) {
                        showErrorAlert(purchasesError);
                    }
                }
            }
        );
    }

About 1% of users affected. I suspect “storeTransaction” or “customerInfo” having null. 

public void onCompleted(@NonNull StoreTransaction storeTransaction, @NonNull CustomerInfo customerInfo)

Should I check

customerInfo.getEntitlements() != null too?