I use Genymotion to test my application, but instead of a PieChart with 3 data, I have a square that is displayed with the color and the label of a last data.
But with a real android device, I have a good Piechart.
This is very strange! I can't say it's something I've seen myself. I don't use Genymoton at work but have used it at home for my own personal projects and have never seen this happen.
As you say, it works on real Android devices so I wonder if it's something to do with the way Genymotion handles OpenGL? It would be interesting to see if you get the same problem using the Android Emulator.