I'm using posts in a slider, whit its permalink in its title. So I'd like to change its permalink equal to an existing page to send users to visualize the page I'm pointing for. It worked until WordPress 4.9 but in WordPress 5.1 it recognize that already exist a permalink like that and it put "-2" after my permalink. To be explicit: on click on post's title in the slider, I'd like that it sends on shop page, not in the post-page they clicked on. So I tried to modify post's permalink from its original permalink to 'shop', but automatically, it changes to 'shop-2'. How can I let WordPress to ignore that?
EDIT
Solved leaving unique slug-permalink and using that code in function.php. Please someone can tell me if is the right way and if there aren't some problem/security issues?
<?php
$page_url_1 = '/post-permalink';
function shop_redirect() {
$shop_page_url = home_url( '/shop/' );
global $pagenow;
if( $pagenow == $page_url_1 && $_SERVER['REQUEST_METHOD'] == 'GET') {
wp_redirect($shop_page_url);
exit;
}
}