Summary:
The player takes fall damage when falling into a cauldron full of water.

Steps to Reproduce:

1. Place a cauldron
2. Place water inside of it
3. In Survival mode, fall into the cauldron from a high place

Observed Results:
The player takes fall damage.

Expected Results:
The player should not take fall damage.

Video:
Minecraft 2020-11-04 13-25-45.mp4