Medium slimes from trial chamber spawners take damage incorrectly when first hit

In the trial chambers, medium sized slimes spawned from trial spawners do not process damage correctly when first hit. This is indicated by an unusually high amount of damage particles, along with the the slime's health apparently being unaffected by the first attack.

To reproduce:

1. Use the seed -723413827163980802 and create a new world.

2. Go to the coordinates -187 -22 -277.

3. Grab a weapon that deals at least 8 damage.

4. Go into survival mode near the trial spawner.

5. Notice that when hitting the medium slimes, they display excessive particles and take an incorrect number of hits to kill.