PHP prepared statement doesn't work with intval() - php

Question

Please look my code:
$insertStmt = $conn->prepare("INSERT INTO orders (OrderID, OrderTrackingNumber, OrderTotal, CustomerID) VALUES (?, ?, ?, ?)");
$insertStmt->bind_param("ssdi", $orderID, strval("Not Ship Yet"), $orderTotal, $userID);
if ($insertStmt->execute()) {
$insertStmt = $conn->prepare("INSERT INTO ordersproducts (OrderID, ProductID, ProductSold) VALUES (?, ?, ?)");
$updateStmt = $conn->prepare("UPDATE products SET ProductQuantity = ? WHERE ProductID = ?");
foreach ($orderedProducts as $orderedProduct) {
$productQuantity = intval($orderedProduct->ProductQuantity) - intval($orderedProduct->ProductAddedQuantity);
$insertStmt->bind_param("sii", $orderID, intval($orderedProduct->ProductID), intval($orderedProduct->ProductAddedQuantity));
$updateStmt->bind_param("ii", intval($productQuantity), settype($orderedProduct->ProductID, "integer"));
if ($insertStmt->execute() && $updateStmt->execute()) {
if ($updateStmt->affected_rows == 1) {
$isSuccefull = TRUE;
} else {
$isSuccefull = FALSE;
break;
}
} else {
$isSuccefull = FALSE;
echo $insertStmt->error . " | " . $updateStmt->error;
break;
}
}
}
At the line of $updateStmt->bind_param, if I convert $orderedProduct->ProductID to int by intval($orderedProduct->ProductID), the updateStmt will not work ($updateStmt->affected_rows = 0). However, I use settype($orderedProduct->ProductID, "integer"); then it will work like a champ. And only this place gets that issue; others work very well.
Why?
Thanks for helping me.