We've built a course using Fluid Boxes, which we love. The end-of-course quiz has a short series of Hot Spot questions that won't play nice in responsive views... or even if designed in the responsive view, it will break when going back to the desktop view. I've taken items out of the fluid boxes. We cannot switch back to Beakpoint for this one slide. Thank you for the link to the Captivate blog, I did find some great info in there on other topics.
I checked the master slide for hotspot: it is using a static fluid box, which is logical since objects are stacked in a location (hotspot over something else). I suspect the problem is linked with it. Custom hotspot question is probably the best choice. I am aware o the fact that you cannot have one breakpoint views slide in a Fluid boxes workflow.