Well i will try to explain it again if you dont mind.
1. Player A use soulfire rune on player B
2. Player B kills player A, but player B still get hits from soulfire rune
3. Player A after death spawns in temple and get skull because player B still receive dmg
It works same with fire bomb or any other kind things with tick dmg
How it should works?
1. Player A use soulfire rune on player B
2. Player B kills player A, but player B still get hits from soulfire rune
3. Players A die, and it that situation soulfire rune change to normal fire dmg, so Player A doesnt take any other consequences for using this rune (it simply should reset after death, player B still get fire dmg, but it shouldnt affect in any way player A anymore)
Thats how it works in rl tibia, if you soulfire someone and die, fire dmg becomes like dmg from fire field from monster, and its not assigned in anyway to player A anymore, it simply resets