The latest version of the theme fixed this a while ago. Are you using an older/outdated version of the theme? Do you know what version you’re using?
There are a few other posts here in the forum that cover how to fix this just in case you are using an older version of the theme.
Remember, don’t completely upgrade/replace if you’ve made adjustments to your Theme files. If you haven’t made adjustments to your page_portfolio.php file, then you could download and replace the new version with your current version……make sure and back up everything first just in case you make an error.
Let me know the status and Theme Version so I can assist if needed.