We are using ACF for user registration form and we also using plugin called “TML” theme my login.
Now we are having problem is that.. radio and checkboxes are not working. They are showing values directly.. instead of giving theme option with radio inputs..
Here is screenshot of ACF field group
https://goo.gl/hh2hHg
Here is screenshot of frontend user form
https://goo.gl/9Kn11N
Here is the url to check form live..
http://artsplus.weiter.ch/kunstler/registrierung/
Have you tried disabling the other plugins on the site? This is more than likely due to some incompatibility. If you can figure out what other plugin or code is causing the problem someone might be able to help fix it.