Hmm i'm not sure i get that… sorry, I am trying to recreate this file that i did in illustrator into sketch.
I drew a circle, and then tried to draw a single line using the vector pen, with a border of 0 to act as a scissor / cut line. I then tried selecting the circle, and the path and then going to edit>paths>split and it was greyed out?
Am i missing something?
In the next 2.2.2 update (hopefully approved soon), this will be easier. But use a stroke width of 1px for the line instead, and then subtract that from the circle. Repeat that for the other segments and then you should be able to split as you expected