Checkbox not showing on Caldera Forms 1.8.7

Hello, we are having an issue with Caldera Forms on our site: checkboxes are not being displayed in our forms. When you look into the code, you can see the element is there but it’s not showing.

We have the latest update of the plugin and the problem persists. Is there a solution?

Thank you.

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