I may be misunderstanding the question :) Looked ok here, two images attached - took the main body of the shaderball, applied a different material to some polys to get a multi/subobject material, changed the scale in the Triplanar and it seemed to work ok. Just random test materials used. Let me know if the scenario you are looking at is different!
Daily from Jan 11th 2017 used here.
Thanks for getting back.
Something strange is happening to a scene I working on at home. I have a Multi/Sub material where CoronaTriplanar refuses to work with any geometry. Scale, offset, rotation nothing works. If I pull out that specific material from the Multi/Sub one and I apply it alone to any object, it works.
I tried also the BlendedBoxMap and it has the same behaviour. Just doesn't work under the same conditions.
All the other materials in the scene (included other Multi/Sub + Triplanar) they work as they should.
If you want, I can send you some more info tonight once back home.
Thanks!