If a customer searched their site using Google Search and found out that they saw a percentage showing beside their site name (sample screenshot below), The presence of a % sign in the search results for a WordPress website is likely caused by improper encoding or decoding of special characters in the page title or meta tags. 

To remove the % sign from appearing in the search results, you will need to manage this by using SEO plugins like Yoast SEO or Rank Math SEO plugin.