Hi,
Yes, the products are indexed for each category they are in.
Remove the lines:
->select('c.category_name AS category, c.category_alias as categoryalias, c.category_published AS cat_state, 1 AS cat_access')
$case_when_item_alias = ' CASE WHEN a.product_alias != "" THEN a.product_alias ELSE a.product_name END as slug';
$query->select($case_when_item_alias);
and:
->join('LEFT', '#__hikashop_product_category AS pc ON a.product_id = pc.product_id')
->join('LEFT', '#__hikashop_category AS c ON pc.category_id = c.category_id')
from the file plugins/finder/hikashop/hikashop.php and it should prevent that.
Let us know how it goes. Ideally, we could have an option in the plugin to activate or deactivate that.