Subtract leaves trailing vertices

[OGPowell]

I'm using the substract function to subtract two concave solids from each other, and I've run into an issue where vertices are "left over" from the subtraction process.

Here is a graphical representation of the issue. The subtract process should leave something like this:

But instead, the substract function leaves trailing vertices, like this:

Do you know what might be the issue here? Attached is the link to a failing test, and a .json file with the points of a test solid.
https://github.com/OGPowell/Csg/blob/master/Csg.Test/SubtractTest.cs#L62

[[[744.585, 734.575, 97.125],
[1062.208, 734.575, 97.125],
[1062.208, 276.028, 97.125],
[889.654, 276.028, 97.125],
[889.654, 504.099, 97.125],
[744.585, 504.099, 97.125]],

[[744.585, 734.575, 1297.125],
[1062.208, 734.575, 1297.125],
[1062.208, 734.575, 97.125],
[744.585, 734.575, 97.125]],

[[1062.208, 734.575, 1297.125],
[1062.208, 276.028, 1297.125],
[1062.208, 276.028, 97.125],
[1062.208, 734.575, 97.125]],

[[1062.208, 276.028, 1297.125],
[889.654, 276.028, 1297.125],
[889.654, 276.028, 97.125],
[1062.208, 276.028, 97.125]],

[[889.654, 276.028, 1297.125],
[889.654, 504.099, 1297.125],
[889.654, 504.099, 97.125],
[889.654, 276.028, 97.125]],

[[889.654, 504.099, 1297.125],
[744.585, 504.099, 1297.125],
[744.585, 504.099, 97.125],
[889.654, 504.099, 97.125]],
    
[[744.585, 504.099, 1297.125],
[744.585, 734.575, 1297.125],
[744.585, 734.575, 97.125],
[744.585, 504.099, 97.125]],

[[744.585, 734.575, 1297.125],
[744.585, 504.099, 1297.125],
[889.654, 504.099, 1297.125],
[889.654, 276.028, 1297.125],
[1062.208, 276.028, 1297.125],
[1062.208, 734.575, 1297.125]]]