Why highlightPreTag not working?

import React from 'react';

import { Input } from "antd";

import algoliasearch from 'algoliasearch/lite';
import { createAutocomplete } from '@algolia/autocomplete-core';
import { getAlgoliaResults } from '@algolia/autocomplete-js';

const searchClient = algoliasearch(
    'N0HJZGRREO',
    '39c297a49af706fe3cada3f4ba74579d'
);

export default function App() {
    // (1) Create a React state.
    const [autocompleteState, setAutocompleteState] = React.useState({});
    const autocomplete = React.useMemo(
        () =>
            createAutocomplete({
                onStateChange({ state }) {
                    // (2) Synchronize the Autocomplete state with the React state.
                    setAutocompleteState(state);
                },
                getSources() {
                    return [
                        // (3) Use an Algolia index source.
                        {
                            sourceId: 'pages-source',
                            getItemInputValue({ item }) {
                                return item.query;
                            },
                            getItems({ query }) {
                                return getAlgoliaResults({
                                    searchClient,
                                    queries: [
                                        {
                                            indexName: 'pages',
                                            query,
                                            params: {
                                                hitsPerPage: 4,
                                                highlightPreTag: '<mark>',
                                                highlightPostTag: '</mark>',
                                            },
                                        },
                                    ],
                                });
                            },
                            getItemUrl({ item }) {
                                return item.link;
                            },
                        },
                    ];
                },
            }),
        []
    );

    return (
        <div className="aa-Autocomplete" {...autocomplete.getRootProps({})}>
            <Input
                {...autocomplete.getInputProps({})}
                placeholder="Search..."
            />

            <div {...autocomplete.getPanelProps({})}>
                {autocompleteState.isOpen &&
                    autocompleteState.collections.map((collection, index) => {
                        const { source, items } = collection;

                        return (
                            items.length > 0 && (
                                <ul {...autocomplete.getListProps()}>
                                    {items.map((item) => (
                                        <li
                                            key={item.objectID}
                                            {...autocomplete.getItemProps({
                                                item,
                                                source,
                                            })}
                                        >
                                            <a href="javascript:;">{item.title}</a>
                                        </li>
                                    ))}
                                </ul>
                            )
                        );
                    })}
            </div>
        </div>
    );
}

hitsPerPage is working but highlightPreTag and highlightPostTag not working.
Thanks for your help.