Pie chart data visualisation bug

I'm using the DataVisualization charts library. it works perfect but from time to time (I didn't succeed to reproduce it in purpose) There is contradiction between the data in the Legend and the Pie itself, as you can see in the picture below.

开发者_开发问答

If it would happened all the we could assume it is a Binding mistake but it happen very rarely. The code is very complex so I prefer not to share, unless there is no choice.