Subgraph nodes that contain unsupported nodes, both directly and indirectly, are not marked as such.
also, reimporting shadergraphs that use it don’t output a warning or error notifying that there is an unsupported node.
I have created an incident for it, IN-60163
Yeah; this is because, at the subgraph level, we don’t know if you’re going to use the node for MaterialX output. You might, for instance, use the MaterialX keyword to use the subgraph output only for Unity, rather than in generated MaterialX. However, it probably makes sense to assume MaterialX output and mark the nodes just to be maximally informative.
This, on the other hand, is definitely something we should be doing.
Thanks for the report!