Mobs make a constant "Fire extinguishes" sound when standing in lava in rain.
How to reproduce:
Place lava on the ground.
If it's currently not raining, execute the following command:
/weather rain
Spawn a mob in the lava.
Expected result:
The mob would not play the fire extinguishing sound since it never actually extinguishes.
Observed result:
The mob plays the fire extinguishing sound every tick.
Can confirm.