Why is the redux store full of duplicates?

Question

React

Good afternoon! I was faced with the task of implementing pagination, for this the following steps were taken:
The first step was to create a new function in the reducer:

case SET_CURRENT_PAGE: {
    return {
        ...state,
        currentPage: action.payload
    }
}

The second step was to create a network request:

useEffect(() => {
        axios.get(`/post/${props.numbersPage.currentPage}`)
            .then(res => {
                res.data.forEach(item => {
                    props.addPost(item.id);
            });
    }, [props.numbersPage.currentPage]);

In order for useEffect to work after changing the current page, the dependency specified currentPage.
The last step is adding page rendering:

<div className="page">
    {pages.map((page, index) => <span 
        onClick={() => dispatch(setCurrentPageAC(page))} 
        key={index}>{page}
    </span>)}
</div>

Everything works fine, except for one thing, but why, when I click on the span, the old state of the redux store is not overwritten by the new one, the old records remain, and a new response from the server is added to the end. This is not the first time I encounter this problem, I can assume that I may be copying in the reducer incorrectly. Who knows how to solve this problem?