It’s not that Blizzard wasn’t aware of this as it was pointed out in the PTR and they had weeks to fix it.
https://us.forums.blizzard.com/en/d3/t/2610-ptr-consolidated-season-theme-feedback-thread/22932/2
I’m actually waiting for the first HC charactes to complain getting killed because of monsters reflecting the damage of their spawned seasonal clones.