Hey Mark, I noticed your FAQ mentions that there would never be mechanically functional errata to cards; what's the explanation for Training Grounds then? The original rules text, as well as the ruling info, both state that you can choose to discount a creature's activated ability by just 1 or even 0 if you so choose, but with the Aftermath reprint, you no longer have a choice and you're forced to take the full discount of 2. Sounds like a mechanically functional change to me.

We do occasionally make small functional errata changes on cards, but it isn’t something we do a lot.

Hi mark i have some unruling question related to "X". Can training grounds reduce the cost of his third ability while he is in one of my opponents hand? Secondly if i use a clone effect to copy "X" what happen when i put it in one of my opponents hand?

Cards that affect creatures in the battlefield (as most cards do) won’t affect X when he’s not on the battlefield. If you clone X and put it into your opponent’s hand, it reverts to a Clone as it leaves the battlefield, but does end up in your opponents hand (as a Clone that they can cast if possible - you still own it for purposes of cards that care about ownership).