Brief We have updated the files 'block_categories_list.php' and 'products_functions.php' for version 3.6.
Description 1. A tree-type view category list for products was not working properly. 2. Products(Sub-Categories) List block displayed all categories instead of the subcategories of the selected category only.
Further, extract the above mentioned files into the 'blocks' and 'includes' folders of your shop. Do not forget to make a backup copy of the current files in case something goes wrong.