Asigning task to specific groups

Hi! I have created a process model in which a validation is needed depending on the group of the user

In this case, if the user is from the group "CPF Proveedores", a validation Interface should appear as a task for the users of the group "CPF_Gestores". In order to fulfill my objective, I configured the User Input t

In order to fulfill my objective, I configured the User Input task this way:

But the fact is that, when I enter as the user from "CPF_Proveedores", the validation interface appears to me, instead of leaving it as a "pending status" until the user from "CPF Gestores" approves/rejects it. This means that the logic of detecting the user is correct, but the interface is shown to CPF Proveedores too.

What am I configuring wrong? 

Thanks a lot for your time