Why do some unique passives that only exist on one item have names?

The point of naming unique passives is so they don't stack across multiple items with the same passive, like Spellblade and Rage.

However, there are certain items that have named passives despite said passives ONLY existing on that one item.

Runaan's Hurricane: Wind's Fury Phantom Dancer: Spectral Waltz and Lament Dead Man's Plate: Dreadnought and Crushing Blow

Frozen Mallet is the only item that has a passive labeled Icy (which I know is a hold-over from when Phage's passive was the RNG version of Icy), but Iceborn Gauntlet's slowing field is considered Icy in the game engine IIRC, so it only half-counts.

Yeah, just a thought that was on my mind.

(On an unrelated note, the active on Wooglet's Witchcap isn't named Stasis on the tooltip. This isn't actually an issue at all since Zhonya's doesn't exist on Treeline, but I just found it interesting.)