System.unloadplugin(uint handle) not working


I’m creating a dsp using the system.loadplugin() (it is a .dll VST2 plugin)
I call after that createDSPPlugin().
Everything is working as expected.

When i call the system.unloadPlugin() it seems it does not unload it. I mean FMOD returns FMOD.RESULTS.OK but i can still access the handle with an external tool that communicates with the VST.

Is this a bug ?
Is there any other options to destroy a plugin handle ?

I need help ! It make crash the Unity Editor and my software because i need to destroy an recreate my FMOD system and reload the vst plugin. By doing that it spaw one instance of the vst each time i destroy and recreate the FMOD system !

I need to destroy the FMOD system because I need to go from RAW mode to automatic mode to be able to use 3d sounds positionning…