Rest API deep filtering

http://localhost:1337/products?_where[_or][0][product_categories.slug]=phones-and-accessories &_where[_or][1][product_subcategories.slug]=phones-and-accessories

Above query is expected to return all products with either product_categories.slug=phones-and-accessories or product_subcategories.slug=phones-and-accessories

Suppose there is a scenario where there are products with product_categories.slug=phones-and-accessories and no product with product_subcategories.slug=phones-and-accessories.In this scenario, strapi returns null as output for postman response instead of returning products that meet the first part of the or condition.

Is this a bug or expected behavior?