The root cause of the issue is that the printable/saved copies are rendered using the Chrome engine; the radio/checkboxes are disabled in this read-only copy so what you're seeing is how they are rendered by Chrome much like the would be if you were looking at a disabled radio in the browser.

I managed to work around this with some complicated CSS is the classic designer. The CSS would probably be quite different in the new layout designer, but what I did for the classic forms might at least provide a decent starting point for the CSS.
Checkboxes and Radio Buttons Forms PDF/TIFF Generation - Laserfiche Answers