ImmediateModeShapeDrawer not drawing duplicated shapes

Hi,

I'm trying to wrap shapes into a ShapesManager, child of ImmediateModeShapesDrawer.
I noticed that drawing twice the same type of shape in the command makes that shape not drawing at all.

Here's the code I used to debug my manager : 

Here's the result in play mode (spheres not drawing): 

And here's the result when I remove line 52 (working as expected for L50-51): 

To explain a bit the Manager outside of my debug : 
The manager receive gizmos from the code 
the "gizmos" used are Actions calling Draw's methods

So I have one Command drawing all the needed shapes
(not sorted yet for batching)