S21 Mundu Set: elites HP stuck without Pylon

Season 21: In the last 3 days only I get this very annoying thing.
In group play (GR110 + 2-3-4 players) I casting only 5-10 Spirit Barrage stacks, then always break it manually.

  • If we don’t get pylon usually the elites HP stuck at like 15-20%.
  • If we get pylon there is no problem.
  • I try short casts and long casts also but doesn’t help.
  • Other players also try dealing damage, but that elite don’t want to die.