Sion W passive bug
I've noticed that whenever Sion kills a large monster (like scuttle, dragon, or Gromp) he doesn't get the bonus 10 health. Like if I kill Blue Buff he will get 4 bonus health from the little creeps but nothing from the blue bluff itself. I've killed the entire jungle except Rift Herald and Baron and I never got the bonus 10 health from any camp.