Villagers and mobs are spawned in floating and offset in villages upon world generation, occasionally getting stuck and suffocating

The bug

Villagers, zombie villagers and passive mobs inside villages are spawned into the world one block too high. This causes them to occasionally get stuck, especially since they also are shifted into the wall occasionally.

All types of villagers are affected (unemployed, nitwits, babies, and zombie villagers). Also, all biome variants of villagers are affected.

How to reproduce

1. Create a world with the seed 5322602735514886292
2. Run

   /setblock ~ ~ ~ minecraft:repeating_command_block{auto:1b,Command:"execute as @e[type=villager,nbt=!{NoAI:1b}] run data merge entity @s {NoAI:1b}"}
   

3. Run

   /tp @s -5967 68 2598
   

4. Look around
   → You will notice that all villagers are floating inside of the air, and the villager near /tp -5986 68 2555 even is stuck inside of the wall of its house

If you reproduce this without the command block, most villagers will be able to roam around freely, but some still are stuck in walls.

See another example in this comment.

The cause

All villagers in the villager structure files are spawned on top of the jigsaw block instead of inside of it. Also, some villagers (especially baby villagers) spawn with their hitbox partially outside of the block they're standing in.