This is an example of limitation of wrapped rotary. It is important to understand that the simulation is performed with flat material. That means that the cut will have flat bottom in the flat mode, which then will then become curved when flat material is being wrapped.
For the simulation to look correct, the flat simulation would need to use a properly curved tool shape, so it becomes flat when wrapped.
You could get a correct preview in Aspire, but only if you have used vector unwrapper + two rail sweep + 3d machining which is an overkill for simple shape that can be cut with 6 profile cuts.
Gary's solution will of course work and you will be able to machine the piece, however it won't help with the preview issue. Again this is just a limitation of wrapped rotary and it is not an easy one to overcome.