I had a look into SubGeometry class, and couldn't find a simple fix. All the buffers appear to be invalidated when you use updateVertexData, which is as it should be. (was hoping normals needed to be rebuilt)
I did notice this comment "// todo: send out bounds invalid" I don't know how the bounds are used, or indeed if they are used at all further down the pipeline, but maybe it has something to do with the bounds changing? Any suggestions very welcome :)
