Steps to reproduce

1. Give an entity the minecraft:spawn_entity or minecraft:summon_entity component, and set the component up to spawn/summon a lightning bolt. You can use Messing Around.mcpack, which replaces the evoker's fang/vex spells with a lightning bolt summoning spell.
2. Summon a villager at the position where the lightning bolt will be spawned by the custom entity, such that it cannot move.
3. Wait for the entity to spawn the lightning bolt on the villager.
4. Reload the world.

Expected results

In step (3) the lightning flashes, makes its sound, sets the ground on fire, and turns the villager into a witch.

Actual results

In step (3) the lightning bolt only flashes. After you reload the world in step (4) the ground will be on fire and the villager will be a witch. See Desynced lightning.mp4

Note

It looks lightning bolts used to display this behavior with the /summon command as well: MCPE-17295. Evidently the fix for that issue was not complete.

When attempting to add a component group with the spawn_entity object that summons a lightning bolt, the lightning bolt does appear, but there is no sound, no damage and no fire.

On the same world using the /summon command to summon a lightning bolt does summon a working lightning bolt.