User blog comment:Slashingstrike/Enchantment: Kritalizer/@comment-6726953-20160820035003/@comment-6726953-20160820124938

^Actually, rageblade doesn't have Phantom Hit as a unique passive name. It's listed as Guinsoo's Rage, both in-game and in item sets.

It's a simple mistake if you didn't intend to have them stack, but honestly I think it would be fine if they did; Rageblade has an AP item in it so it's not as useful on champions that build crit (like Vayne or Kindred), it's very expensive, and it needs to be stacked up six times to take effect. It's also one less slot (two if you build Infinity Edge) for a major threat for an on hit (like say, Botrk, a Tiamat item (if melee), Runnan's (if ranged), Wit's End, or Nashor's Tooth).