Revealing hidden text

When I click the print link and after the print dialogue pops up, the text on the page itself will change to reveal a hidden timestamp. Specifically, the WordPress theme I’m using has a hidden rich snippet that appears after the page is printed. If you inspect the date, you’ll see what I’m referring to. Do you know of a way to fix this?

Thanks, and thank you for making this plugin!

The page I need help with: [log in to see the link]