I was fight an Atlantis level on hard and notice all my heroes with counterattack. Elena only does herself and 2 closest allies right? I have emblems on Triton (13) and Elena (4)
That boss has counterattack too I believe.
Mad hatter stole the buff when you fired him and gave it Triton and hatter.
If you tap and hold on the heroes, you’ll find the counter percentage is different.
A hero looses half it’s value if you don’t fully understand his special skill, especially a support hero like the hatter… If I recall correctly, the hatter stoles enemy’s buffs and randomly distributes them between his team mates. In this case, three of your heroes were already buffed by Elena and the other two received it from the hatter.