It appears that when you turn undead with an item altered effect (in this case "Planar Rift") it rolls to actually turn undead and does successfully do so.
You mean, it grants one of the old custom turn undead? It's fine then, old custom turn undead overrides the new ones, so working as intended.
Sorry if I was not clear, using the old custom turn undead overrides causes turn undead to actually roll - and actually turn undead.
It rolls hit dice, it rolls max level of undead turned and then actually turns the undead. If you have the appropriate domains (I.e Good/Evil, Earth etc) It also turns Outsiders or Elementals.
This is in addition to its custom effect