I won’t have time to check your graph today, but the image looks correct other than the polysurface error which I think is likely due to an empty list.
A thought experiment: Go get a piece of paper and a pair of scissors. Cut the piece of paper down the middle. You cut it once, and now have two pieces of paper. Go get a new piece of paper. Cut it three times, and now you have four pieces of paper. Cut the paper as many times as you like and count the paper and the number of cuts. The resulting count will always be one more than the number of cuts. Ok clean up the confetti - we have work to do.
In your example you took a few surfaces (pieces of paper), and split them (the cuts) [once, once, once, three times, once]. The results should be [two surfaces, two surfaces, two surfaces, four surfaces, two surfaces], which is what I see.
Try adding a colors with an alpha value to the split surfaces and disabling the other geometry except for the cut lines. This should visually confirm if things are working out, or highlight why they fail.