I'm using the Searchable behavior in Doctrine to search for products in my catalog. It works great when searching for keywords that do match a product. For example, the keyword "Backpack" returns all products with the word "Backpack" in the title.However, when a search is done for a keyword that doesn't match a title at all then every record is returned. For example, "ASDF" returns all products. Why is this happening and how can I fix it?