I feel like it's a little of both.
I've had issues getting my own attempt to bake pivots into my trees vertex colors but even when I try to get a working example from the demo scene ( https://github.com/sideeffects/GameDevelopmentToolset/blob/Development/hip/pivot_painter_demoscene.hip [github.com] ).
I can only get movement from a pivot at the base of the model:
The rotating material is intentionally there so we can see where the pivot/pivots end up.
Every box should be rotating about it's own axis though.
Every one should have a slightly different vertex color but they are the same shade of blue, this model is exported from the “interactive grass” network:
Any thoughts?