All raiders spawn on the same block, one block above the ground, during a raid

The bug

During a raid, all of the raiders during each wave will spawn on the same block, causing them to explode out after one moves.

This is related to MC-163503.

Steps to Reproduce: provided by [Mod] Avoma

1. Summon a repeating command block that will instantly set all raiders' "NoAI" and "Glowing" tags to "1b" if there are any present within the world.

2. /setblock ~1 ~ ~1 minecraft:repeating_command_block{auto:1b,Command:"execute as @e[type=#minecraft:raiders] run data merge entity @s {NoAI:1b,Glowing:1b}"}
   

3. Place down a bed and summon a villager close to it.
4. Give yourself the bad omen effect in order to start a raid.

    /effect give @s minecraft:bad_omen
   

5. Wait for the raid to begin and locate where the raiders spawned in.
6. Take note as to whether or not raiders are all spawned at the same position, one block above the ground.