Checkbox validation problem since last updates

Hi,

I realized there’s a problem with the checkbox validation since last updates. You can see the contact form in the bottom in estudigrafema.com. If you just check the checkbox, all the fields are marked with error (the same if you click the submit button).

I tried to replace the file contact-form-7/includes/js/index.js by the one of the version 5.5.6 and it’s working. So, the problem is in this file.

Any clue?

Regards.

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