AssignDataToParameter() fails on 0.9.006 ?

Hello everyone

We have C# code that worked fine with GH  0.8.0066 and does not work in 0.9.0006

I narrowed it to the function "AssignDataToParameter" that fails on the newer version.

For example, the basic code:

Rhino5Application rhino_app = new Rhino5Application();
rhino_app.Visible = 1;
rhino_app.RunScript("_Grasshopper", 0);
dynamic grasshopper = rhino_app.GetPlugInObject("b45a29b1-4343-4035-989e-044e8580d9cf", "00000000-0000-0000-0000-000000000000") as dynamic;
grasshopper.OpenDocument(@"C:\Temp\test1.ghx");
bool asignRes = grasshopper.AssignDataToParameter("Num", (Object)0.5);
grasshopper.RunSolver(true);

On the 0.9.0006 version the asignRes gets "false" (and does not change the param of-course) while on  0.8.0066 asignRes gets "true" and everything works fine.

Am I doing something wrong? Did GH automation change? Is it a bug in 0.9.0006 ?

I added the file test1.ghx but its really trivial :)