QBuffer setBufferFunctor doesn't call setData()

I'm not sure if this is a bug due to the recent implementations, but the setBufferFunctor doesn't call setData(). This creates unexpected situations, for example, when a call to QAttribute::asVector*D() is done, the function returns wrong values from a another buffer (sometimes not initialized).
My use case comes form the fact that I need to access the vertex positions of a torus mesh.