The Bug:

Horses, donkeys, and mules with their "NoAI" NBT tag set to "1b" can dip their heads down.

Steps to Reproduce:

1. Summon a horse with its "NoAI" NBT tag set to "1b" by using the command provided below.

   /summon minecraft:horse ~ ~ ~ {NoAI:1b}

2. Watch the horse closely and wait for it to dip its head down.
3. Take note as to whether or not horses, donkeys, and mules with their "NoAI" NBT tag set to "1b" can dip their heads down.

Observed Behavior:

Horses, donkeys, and mules can dip their heads down.

Expected Behavior:

Horses, donkeys, and mules would not be able to dip their heads down.