Steps to reproduce (instant despawn on sim4)

1. Load MCPE-149883 show witch despawn.mcworld (slightly modified version of the test world from MCPE-45183)
2. Press the "start raid" button.
3. After each of waves 1-3 spawn, press the "kill" button to kill the wave.

Expected result

Wave 4 spawns with 3 witches.

Observed result

When wave 4 spawns, the 3 witches instantly despawn (usually, in some attempts they may not). If you happen to be looking in the direction of the spawn you can see them appear then disappear. The raid bar for wave 4 is immediately half empty.

Steps to reproduce (despawn during a raid)

1. In an empty flat world set to sim6 or higher, place a bed and spawn a villager.
2. Surround the villager with blocks to protect it.
3. /effect @s bad_omen
4. When each of waves 1-3 spawn, run /kill @e[type = !villager]
5. After the witches and illagers have made finished their initial pathing to a random spot inside the village boundary, run /tp @s ~ ~150 ~
6. Fall back down to the ground.

Expected result

All 6 raid mobs from wave 4 are still present.

Observed result

The witches have despawned, and the raid bar for wave 4 is half empty.

Witches spawned in a raid on normal or hard mode instantly disappear or don't spawn at all. Starting a raid and getting to wave 4 or 7 should spawn witches but instead the raid bar instantly depletes because they either don't spawn or instantly despawn.