Why mysqli_stmt_bind_param function not working as expected when using prepared query?

When I am using mysqli_stmt_bind_param($stmt, "sssi", $title, $content, $published_at, $id); function for binding the parameters received through post request, It’s working fine as it returns true and execute successfully, But If I use $title instead of $id in 4th parameters as mysqli_stmt_bind_param($stmt, "sssi", $title, $content, $published_at, $title);, then it should return false because we are binding string type to integer as the $title contains varchar type and for this time, I was using the value of $title as alphabetic characters but instead of returning false because of data-types mismatching, it’s returning true.
I know it won’t update the database as I am passing title instead of id, but I just wanted to know the behavior because it’s returning true for mismatched types also.

if ($_SERVER["REQUEST_METHOD"] == "POST") {

    $title = $_POST['title'];
    $content = $_POST['content'];
    $published_at = $_POST['published_at'];
    
    // function to validate empty fields
    $errors = validateArticle($title, $content, $published_at);

    if (empty($errors)) {

        $sql = "UPDATE article
                set title = ?,
                    content = ?,
                    published_at = ?
                WHERE id = ?";

        $stmt = mysqli_prepare($conn, $sql);

        if ($stmt === false) {
            echo mysqli_error($conn);
        } else {

            if ($published_at == ''){
                $published_at = null;
            }            

            // Binding the parameters to prepared query
            $check = mysqli_stmt_bind_param($stmt, "sssi", $title, $content, $published_at, $id);
            var_dump($check);

            if (mysqli_stmt_execute($stmt)) {
                
                print_r("already executed");
                if (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off'){
                    $protocol = 'https';
                }else{
                    $protocol = 'http';
                }
                // header("Location: {$protocol}://" . $_SERVER['HTTP_HOST'] . "/article.php?id={$id}");
                exit;
            } else {
                echo mysqli_stmt_error($stmt);
            }
        }
    }
}