The Bug:

Shulker bullets don't produce bubble particles when moving through water.

When other similar entities such as tridents and snowballs move through water, they produce minecraft:bubble particles, so one would expect the same behavior for shulker bullets.

Steps to Reproduce:

1. Throw a trident in a large area of water and take note of how it leaves behind a trail of bubble particles.
2. Summon a shulker bullet while underwater by using the command provided below.

   /summon minecraft:shulker_bullet ~1 ~ ~1 {NoGravity:1b,Motion:[0.0,-0.17,0.0]}

3. Watch the shulker bullet closely as it moves through the water.
4. Take note as to whether or not shulker bullets produce bubble particles when moving through water.

Observed Behavior:

No bubble particles are produced.

Expected Behavior:

Bubble particles would be produced.