GDScript but not C# is able to set Blend Shapes values via code

[GeorgeS2019]

Godot version: 3.2 (stable) mono

OS/device including version: Windows 10 19014

Issue description:
The attached project shows GDScript (but not a similar c#) is able to set the blend_shape value via code

Steps to reproduce:
See the attached project, run Game scene with 2 sphere, the one (red) with GDscript works, not the green sphere with c#

Minimal reproduction project:
[BlendShapeCsharp.zip]
(https://github.com/godotengine/godot/files/4208427/BlendShapeCsharp.zip)
Ref of the modified project:

Other open issues with blend shapes
Most relevant:
#15778

Other FYI isseus:
#31595
#34658
#24226
#17749

[GeorgeS2019]

In Csharp, BlendShape are get and set through two classes
ArrayMesh.cs and VisualServer.cs

Interestingly, in ArrayMesh.cs there is no corresponding SetBlendShapeWeight method
Could this explain why the above bug happens?

================================================
There is this method in VisualServer.cs

/// <summary>
/// <para>Sets the weight for a given blend shape associated with this instance.</para>
/// </summary>
[GodotMethod("instance_set_blend_shape_weight")]
public static void InstanceSetBlendShapeWeight(RID instance, int shape, float weight)
{
     NativeCalls.godot_icall_3_630(method_bind_262, ptr, RID.GetPtr(instance), shape, ref weight);
}

[BastiaanOlij]

instance_set_blend_shape_weight is a method that is called from MeshInstance and takes data from the mesh instance consuming the mesh. I'm guessing each mesh instance can set their own weights even when they reuse the same mesh.

If you try and call that method on the visual server and pass it an ArrayMesh instead of a MeshInstance I can imagine it will crash.

[neikeq]

From a quick look, you're calling set in GDScript but _Set in C# instead of Set. Could that be the cause?

[GeorgeS2019]

@neikeq I just check, U are right. Next time, I go straight to u without waiting too long here :-)