The Bug:

In the Nether, you can still use water bottles to cause damage to blazes etc. They can also be used to put out fires and campfires. This behavior is not consistent with how other forms of water work in the Nether. Normally, water evaporates immediately when used in the Nether, so it would be logical for water bottles to behave the same way.

Steps to Reproduce:

1. Put yourself into the Nether with the following command:

   /execute in minecraft:the_nether run tp @s ~ ~ ~
   

2. Summon a blaze with the following command:

   /summon minecraft:blaze ~ ~ ~
   

3. Get a splash water bottle and throw it at the blaze.
   The blaze takes damage.