There have been a couple of bugs reported with the blood shard merchant, Kadala. One is on the Live servers and one has materialised on the PTR server. Blizzard are aware of both and obviously plan to fix. Grimiku explains.

Gambling Off-Class
The only exception to the above rule comes into play when a character is purchasing an item from Kadala that they cannot equip (like a Barbarian purchasing a Mojo or Source, for example). In those situations it will be possible for the player to obtain a Legendary item that is not tailored for their current hero.
Examples can help in this case, so here are a few to help illustrate what’s up.
A Barbarian starts spending Blood Shards on a Mystery Mojo, and the game decides that one of those Mojos is a Legendary. Currently on live, that Barbarian loses their Blood Shards, and actually gets no item, because Kadala is bugged in way that keeps her from ever giving a player a Legendary if the item is something they can’t equip. We’re working to fix this issue for patch 2.1.0 so that the Barbarian can successfully purchase a Legendary Mojo (if he or she wishes).
Let’s say the same Barbarian purchases Mystery Shoulders from Kadala, and the game decides they should part of a set. Those shoulders should be something the Barbarian can actually use, like Raekor’s Burden, Spires of the Earth, or Burden of the Invoker. They should not be part of a set that belongs to another class, like Firebird’s or Zunimassa’s. Right now on the PTR, however, there’s a bug that’s causing players to receive off-class items when they shouldn’t be.
It’s convenient to be able to gamble class-specific items for other classes you have, as illustrated in the top example, but obviously when it comes to set pieces Kadala has no way of knowing that it’s for another class, so the smart loot mechanic has to apply. It would be useful if you could select a check box to indicate you’re gambling for only the class you’re currently using, or 1 or more additional classes.
The second blue post of note today is that there is going to be a change to the Demonic Organ drops. The drop rate will not be altered but in multiplayer games instead of everyone having individual chances of an organ dropping (current situation) it will be group-wide. If an organ drops all members of the party will receive one. This change is live the PTR server just now. As magic find has no effect on the drop rate it seems the most logical (and fair) way to handle this.
Again, Grimiku, explains this one:

This does not influence the drop rate (and the rate will continue to scale in the same way with difficulty), but it will make sure that groups that stick together will all be on the same page for what’s needed to complete a Hellfire Ring or Amulet.