Mailchimp Form notifications with "I agree to terms & conditions" = false

Hi
we have received a number of email notifications of blank form submissions.

We are using the Newsletter via Mailchimp functionality with the option of Append a Privacy Policy Message to Mailchimp contact forms ticked.

The two fields, email and fullname, are empty and the “I agree to the terms and conditions laid out in the [av_privacy_link]Privacy Policy[/av_privacy_link]” is false.

I have tried every device / browser option I can lay my hands on to get past the validation but none let me submit a form without completing the mandatory fields including ticking the I agree field.

Please can you advise possible solutions.

Thanks

John