So I feel kinda silly, but I found out what the solution was. When the spline is outside of the boundary of the pcg volume, it will not update correctly, even when the node for the spline sampler has unbounded selected. It just had to have the pcg volume that contains the graph touch the spline for it to work correctly.
Welllll if anyone else runs into this obstacle, at least they can view this page and see where my error was ha ha ha