In previous versions of 4D, radio buttons had the additional option to automatically be grouped if the variable name started with the same letter (E.G. r_1, r_2, etc.). The option continued to stay through the current versions of 4D as a compatibility setting "Radio buttons grouped by name".
However, due to the new structure of project mode, this compatibility will now be switched off upon project conversion. When working with any radio buttons, be sure that the radio buttons are either grouped using the Group tool or that the buttons belong to the same "Radio Group" name in the button properties.