onDamage onhit attribute

testing:
  Skills:
  - onDamaged{d=200;oS=testing-start;oH=testing-hit} @Self
testing-hit:
   Skills:
  - damage{a=10}
testing-start:
  Skills:
  - msg{m=startskill} @Self

testing2:
  Skills:
  - onDamaged{d=200;oS=testing-start;oH=testing2-hit} @Self
testing2-hit:
   Skills:
  - damage{a=10} @trigger

In this case, the damage skill will damage the caster but not the attacker. I tried @target/@trigger but also not working. I'm using the newest dev version Build 3596 and paper 1.16.4