Can Karthus and i guess Sion only lose 8 stacks when they die?

Their passives are only useful when they die which is counter intuitive to stacking. So they more or less have to fight with only 4 of their 5 "skills" in order to keep the stack count increasing, so losing only 8/10 (4/5) of the stacks would be fair in my opinion. Also since these passives do not somehow revive them, they always lose stacks (unlike say Zac, Zilean, or Anivia).

Edit: If it was not clear, I am talking about .