Encountered something weird when building my first interactive dashboard (thanks for the awesome course, Mynda!)

I have a combo box set up to toggle a pie chart between two different data sets. 

When I toggle it to one option, the pie chart looks great. It's accurate, it's lovely, it makes sense.

When I toggle to the second option, the pie chart disappears.

So then I tried a donut option, just to see what happens. Now I have one toggle as a pie chart and one toggle as a donut chart. At some point I got two different donuts, one with an "explosion" at the center that I couldn't undo. But we seem to be back to the pie/donut, inexplicably. Nothing has changed about the data set.

This is clearly not the end of the world, but it is bothering me. Why can't I get the pie on both? 

If it helps, I need to do this on a Mac (I know!) and data from two pivots (I know! I know!) so I set up a workaround; the data set is a simple sheet using the IF and GETPIVOTDATA functions to populate.