[split] Does Voynichese evolve from A to B?

[npcompl33t]

small topic-specific vocabulary, developed haphazardly, and no stable grammar -
Nothing like Rohncese.

I'm not sure if you read the grammar paper, but it seems to describe Rohncese exactly like this, shifting and unstable grammar, with certain portions appearing very half-hazard. Pidgin may still be a bit of an oversimplification, but the language looks exactly like what you would expect from a solo-medieval designer. Creating coherent grammar is extremely complicated, and the creator seems to have made certain things up as they went along, with shifting rules being one of the main difficulties in resolving ambiguity and creating consistent translations. 

If the VMS were to lack any type of observed similar evolution, in my opinion, it would actually be substantial evidence against it containing meaning. 

It is extremely unlikely that over the course of writing such a long document in a novel writing script such changes and developments would not occur. Such changes were occurring rapidly across different writing systems in known languages at this time. The idea of the VMS representing a perfect unchanging script is not only at odds with the traditional Currier A/B split, or the chronological gradient, its assuming a fantasy level amount of skill on the part of the creator to develop a completely perfect writing system.