Why one user can't change the password if the user have Full Control over the Group?

Hello all,

Let's take an example to explain a scenario. 

I have one user named 'demop' which have full control over the Group named 'weak_permission' which contains a user named 'victim'. Now, I tried to change the password of the Victim but I got an error saying, 'Access Denied'.

As the user have full control over the group then it should have the full control over the user under the group also, then why I am facing the error. I also checked theAdcount attribute, it was not there, any where so what am I missing here?

Thanks & Regards