Sorry I have been away for a while, so can you please let me know what is the situation if two of these are out and the Reaction triggers? Thanks

Each can trigger and resolve separately when a trooper leaves play up to 3 times in the phase for each copy.

If you have two copies of Imperial Discipline, when one of your Trooper units leaves play you may trigger the Reaction of Imperial Discipline twice. Remember, however, that you can only use the Reaction of Imperial Discipline 3 times per phase.

EDIT: Do we have clarification that "Limit X per Y" is per card?

If you have two copies of Imperial Discipline, when one of your Trooper units leaves play you may trigger the Reaction of Imperial Discipline twice. Remember, however, that you can only use the Reaction of Imperial Discipline 3 times per phase.

EDIT: Do we have clarification that "Limit X per Y" is per card?

So to be clear: two imperial disciplines. 3 troopers leave play. I activate Imperial discipline off as many triggers as possible. Does my opponent distribute 3 damage or 6?

6 damage

Great. That's how I read it. Thanks.