Like the subject says. It doesn't show up in the modal, and when you click submit it redirects you to the register.php page and shows that you need to check the box.
Also, the Captcha does not align properly in the modal. You can still see it and fill it out, but it's just a little wonky in appearance.
I redirected the "Register" button link to the Register.php page as a quick fix.
This was tested in "bootstrap", "united", and "simplete".
For your convenience.
Thanks for your time!
Blessings to you!