I'm not sure if the 'trigger' functions are wholly changed. Normally, every classes that rely on 'trigger' function will have their actions counted by the number of time they attack. And those counted actions will have a chance to trigger another attack of other heroes, depending on each hero's aura.
In the past, a shadow class which can attack multiple times per round has their actions counted per the number of time they attack in one turn. So other classes that have synced auras can take advantage of the 'trigger' multiple times per turn.
This rule applies to all 'trigger' functions in battle system. Some examples are: 1) If you get attacked multiple times in one turn, you get more chance to get healed multiple times per turn. 2) If you attack multiple times in one turn, you get more chance to do continual chain attack with other heroes with synced auras.
The recent change I found is that a shadow class's multiple attacks in one turn are counted as a single attack when staying next to heroes with auras that allow others to attack and heal. I haven't had a time to explore if other 'trigger' functions have been changed to be functioning the same. But if other 'trigger' functions still count every action separately for triggering chain attack, it will be very unfair. All skills with the same 'trigger' functions should be working the same way whether or not it is active action (attacking) or passive actions (being attacked). Some active action of shadow attacking and healing in aura should not be singled out and being downgraded while other 'trigger' functions still work the same way.
All in all, if the change are applied to all 'trigger' functions, I view it as an increased difficulty of the game by nerfing chain attack. If the change is only made to "a shadow class's multiple attacks in one turn are counted as a single attack when staying next to heroes with auras that allow others to attack and heal", then it's very unfair.