I just wanted to make note that there are two distinct interactions between crackling doom that are happening currently. I am hoping using my zeta on Vader was not wasted. But allow me to explain the two issues separately.
Enemy has shock, emperor palpatine ends turn, crackling doom applies DAMAGE to the enemy, and the enemy does not get the TM reduction from Darth Vader's zeta. Not 50% of the time. Not even 1% of the time. Never. - think of the videos of p3 z Vader and Palp teams.
The other distinct time crackling doom is used and the TM reduction DOES work. Is against Jedi. Palpatine turn ends. Crackling doom happens. And 50% of the time, 25% turn meter goes poof. It works very well.
The similarities are none of the mentioned targets are being focused on. So these are the collateral damage enemies if you will.
I think the targets who have been shocked, and are receiving damage should intact be losing 25% TM half the time. However it is none of the time currently. The leader ability and crackling doom work fine on Jedi whether shocked or not.
Edit: this has been posted and replied to as being investigated by cozispoon. My apologies. Carry on investigating please.