When creating a trial group in Group Finder with enforced roles (e.g. 2 tanks, 2 healers, 8 DPS), the system behaves incorrectly if a player switches role after joining.

Steps to reproduce:

1. Create a trial group with 2 tanks required (Enforce Roles enabled)
2. A player joins as tank
3. The player switches role to DPS after joining
4. Remove (kick) the player from the group
5. Attempt to set tank count back to 2

Result:

* Group Finder does not allow restoring the original role setup
* It behaves as if the tank slot is still occupied
* The group becomes stuck with incorrect role composition (e.g. only 1 tank possible)

Expected behavior:

* Role counts should always reflect the actual current group composition
* After removing a player, roles should be fully adjustable again

Additional issue / suggestion:

* Players should NOT be allowed to change their role after joining a group created with "Enforce Role Requirements"
* Alternatively, changing role should automatically update the group composition and free the original role slot

This behavior allows players to unintentionally or intentionally break group compositions.