What you were expecting to happen, and what actually happened
I expect that wight life is increased by the life removed from the enemy targeted by wight spell.
But the life given to wight is always the value in wight spell description. Example:
Assume wight life is 50 and wight spell steals up to 20 life (remark: wight gets +4 extra life if the enemy dies):
- use its spell on an enemy with life = 30 => enemy life = 10, wight life = 70 (50 + 20) =>OK
- use its spell on an enemy with life = 15 => enemy dies, wight life = 74 (50 + 20 + 4) => KO, wight life should be equals to 69 (50 + 15 + 4)
- use its spell on an enemy with life = 50 under faerie fire => enemy life = 20, wight life = 70 (50 +20) => KO, wight should be equals to 80 (50 + 30)
How often does this happen? When did it begin happening?
Always
Steps to make it happen again
Use wight spell on a troop with less life than maximum life stolen by wight spell (typically in normal explore mode).