PK for product_related table

The Primary Key for the jos_hikashop_product_related table needs to include product_related_type because this table is used for more than one type. With out the type being added to the PK the INSERT IGNORE will not add rows where the product_id and product_related_id are already in use for a different type.

You're right. We'll add that query in next release to change the primary so that you can have other types in that table without conflicts:
ALTER TABLE `#__hikashop_product_related` DROP PRIMARY KEY ,
ADD PRIMARY KEY ( `product_id` , `product_related_id` , `product_related_type` )