Caveat for all answers: I’m pretty sure no one here has tested ProBuilder.
Short answer: No, that has nothing to do with PolySpatial in anyway, nor should it block used of ProBuilder in PolySpatial. If it’s not working, this is most likely not the problem.
Long Answer: That’s usually because something in that class in ProBuilder is compiled differently for a target platform than editor. Usually because some set of serialized fields in the type are wrapped with an #if UNITY_EDITOR/#endif block. What happens is that the serialized asset will have data that is for both runtime and editor, but when loaded at runtime there are fewer fields to read in than the serialized asset contains.