Change record status: 
Project: 
Introduced in branch: 
2.0.x
Introduced in version: 
2.0.0
Description: 

I don't think anyone ever tried to, but having a plugin, which ultimately is responsible for the relation between a group and an entity, target said relation itself seems like a crazy thing to do, right? Well, turns out it is, but I simply forgot to disallow it. So that's fixed now.

Impacts: 
Module developers
Site templates, recipes and distribution developers