[General] Enabling Yes, users of this group can access the admin CP removes limit on max privat

[alex10455]

Enabling  "Yes, users of this group can access the admin CP removes limit on max private messages"

Why does enabling such settings on a groups with ACP access removes the limit??? I don't want it like that.
And yes, I've created another group and same problem. 
And yes, they don't have permission to edit group settings

---

Bump, I still need help.