Quiz not allowing student to select answer choice in quiz

I am experiencing the same issue after having upgraded to 360. I have re-published a course today in Studio 360 which was originally published in Studio 9 to overcome an issue with the course freezing halfway through. I have fixed the issue with the course freezing but now all of my multiple choice questions are not showing the radio buttons as selected when I have tested answering them. The blue highlight shows but not the black circle which fills the radio button. I am testing in Scorm Cloud and have tried re-publishing with no HTML and only Flash but still have the same issue when I open in both Chrome and Internet Explorer.

Please can you advise if this issue is now being looked at by Articulate? I do not want to have to rebuild the questions as there are 40 questions throughout the course and I have another 18 courses to review.

Incidentally - I did experience the same issue a few weeks ago and managed to get around it by downloading a free copy of Studio 13 and re-publishing the course in that. The radio button problem did not happen then. However- my free download has now expired so I am assuming I can't use this work around again?

Any help gratefully received!