The bug
Lightning bolts convert dying mobs and the converted mob has full health.
How to reproduce
Summon for example a dying pig
/summon pig ~ ~ ~ {Health:0f}
Summon a lightning bolt before the dying animation of the pig ends
/summon lightning_bolt
→ You will notice that a zombie pigman is spawned
Linked issues
is duplicated by
relates to
Comments

Confirmed in 17w17a.