So turns out your ramp works correctly when attached to a larger part, like so. So that's a thing.
Edit: I changed the node size from 3 to 2 thusly and now the ramp works as intended I think. node_stack_top = 0.0, 1.50, 0.0, 0.0, 1.0, 0.0, 3 ---> node_stack_top = 0.0, 1.50, 0.0, 0.0, 1.0, 0.0, 2