Problem with dynamic VDB re-deploy when it contains a Virtual Model

I am using the AdminAPI to add a View Model to a dynamic VDB. The initial deployment succeeds - the VDB deploys and i can query the View.

However, then I retrieve the VDB via the Admin API. In debug, I can see on the view model - that the schemaText field is now null. If I attempt to make other changes and re-deploy, the re-deploy fails - the parser chokes on the null schemaText