The commonly understood semantics for radio buttons is that the selected radio button is filled on the inside (e.g. with a foreground color). The new styling does not fill the inside, and as such is a bit more confusing. I had to do a double-take at first, even though I had developed the screen I was looking at. It's important for a design to use standard and shared understandings that immediately communicate with the user.
Change the style back to a filled in circle, and for the Bootstrap 3 theme in particular please change it back to match Bootstrap 3.