There is a whole bunch of bounty-specific legendaries that only drop in Horadric Caches and for specific Acts in which you performed the bounties. I already got some of those bounty-specific legendaries, but no generic legendaries from the cubes so far.
Do Horadric Caches only drop these bounty-specific legendaries? Or can they drop any legendary in the game?
From a blue post on the official Diablo 3 forum:
To clarify: Horadric Caches can drop any type of Legendary (regular or Bounty-exclusive) EXCEPT those that require Torment difficulty on higher. As difficulty has no impact on Horadric Caches, this also includes the ability to drop Torment-only Legendaries.
Kadala is similar, as she also cannot generate Torment-only Legendaries.
Only the gear from monsters, including Rift Guardians, is affected by Difficulty level.
Kadala – Can now drop Torment only Legendary items
Source : Link , Question Author : Mad Scientist , Answer Author : Community