There appears to be an issue with the Flying Edges algorithm that can cause a crash on some platforms and some odd results in others. To replicate, load in this data: [test.vtk](/uploads/caed1cbe602ef2b94b7bad8f5134cea6/test.vtk) Then, run the `vtkm::filter::contour::Contour` filter with an isovalue of `300`. (Actually, lots of middle range isovalues cause the issue.) On some builds, you will get an assertion failed in the `MapPointField` worklet (in `vtkm/filter/contour/worklet/contour/FieldPropagation.h`). In others, you will get a bizarre corner go way out of the space. I think the problem in both cases is that the interpolated edge ids that are supposed to be computed in flying edges pass 4 are not being written in some condition, and some uninitialized garbage portion of that array is later used when mapping fields.