If they worked in Legends PvE, enemies would be able to counter several of legend's stronger powers. Ra's Al Ghul has a brawling blockbreaker in the newest PvE legends that can be interrupted.
Well they didn't work in the Courthouse at all and they dont work in the first 3 bosses of LOA, what's the point of the counter system if it's only implemented part of the time.
Imo legends pve has been a hot mess. 1rst courthouse has no counter mechanics at all and was probaly the worst choice as the 1rst alert for this mode. Then what happened with loa 2day. SMH
They don't don't work because those instances don't have counters from NPCs. The regular versions don't as well.