Torment Scarab of Possession Is Not Stacking Properly

Unsure if this is the intended behavior: According to the wiki and all documentation I could find, the intended behavior of the scarab is:

Per Torment Scarab of Possession:

+25% Chance For Rare Monsters To Be Possessed By Up To 3 Spirits.

So, with the limit of 3, it should be:

75% Chance for Rare Monsters To Be Possessed By Up To 3 Spirits

Instead, the behavior CURRENTLY works like this:

25% Chance For Rare Monsters to Be Possessed By Up To 9 Spirits.


I am not sure if this is an undocumented change, bug, or what.