Stray cut path!

I am getting a stray cut path when I de-select climb cut in a pocketing operation. The cut path goes well outside of the drawing. What is going on? Job is attached.

You can very occasionally get issues like this. Changing the stepover usually fixes it. for instance a sepover of 49% or 51% will work. In this particular case 50% stepover results in a problem on each arm of the shape.