There IS an issue with this mod that has been brought to my attention, however our server is not running the latest version. Not sure if it's one that you have fixed.
If a player receives a stalkers ring, they have 5hp and can knife only.
If they receive stalkers ring then /changerace and select assassin the game will say they have 'no item'. However they still have the ring in hand, and will still have all the benefits (invisibility) but none of the negative effects (knife only, 5hp)....basically they get their guns back and all their HP, including strength bonus' etc. They are also able to actually get a 2nd item and get the bonus' from both the ring and the new item. When they lose/drop their 2nd item however, they will lose the stalkers ring.