Passengers can glitch through walls and escape out of chambers when their mounts are killed.

Steps to Reproduce:

1. Create a standard 1x2 wide kill chamber surrounded by 1 block thick walls.
2. Summon in 20-30 chicken jockeys with baby zombified piglins:

   /summon minecraft:chicken X Y Z {Passengers:[{id:"minecraft:zombified_piglin",IsBaby:1b}]}

3. Attack the chickens with a netherite sword

Observed Results:
Some, not all, baby zombified piglins glitching out through the kill chamber walls. They take some suffocation damage in the process if wall is made of solid blocks, otherwise they just escape if wall is made from glass. If you make the wall a double layer of glass, you can see some of the baby zombified piglins being stuck inside the inner layer wall blocks.

Expected Results:
Baby zombified piglins should be contained within the kill chamber.

Notes:
This can occur with most mobs riding an entity.