Element not showing in Safari & Firefox

Hi All,

In one of my prototypes I use a radio button to toggle (show/hide) a contact form.
It works perfectly fine in preview and in Google Chrome. However, the form does not show on Firefox and Safari. I’ve had multiple people testing this on all kinds of devices, and it happens for everyone.

The prototype is rather old. We have continuously worked on it for at least two years.

I am wondering whether “elements not displaying” is a known bug within Axure 8? Or do you think this is an individual bug in our file, since we’ve been simply working on it for so long?

Edit: Unfortunately I cannot share the prototype, due to a NDA