Cant remove from hasMany when exists elsewhere in class

[Schlogen]

Basically here is my problem. I have these 2 classes:

class User
{
      String name
}

class Department
{
	User head

	static hasMany =
	[
		worker: User
        ]
}

I can set the head to a user account
I can add that same user account to "workers" department.addToWorkers()..

The problem is when I attempt to remove that same user account from workers

department.removeFromWorkers().. I set failOnError to true and there are no errors or any other red flags, however it simply does not work.

Any help would be appreciated!