The Bug:

Arrows of splashing, otherwise more commonly known as arrows of water, don't extinguish burning blocks or entities.

The triaging/fixing of MC-203553 and MC-189911 suggest that water in the form of items, in these two cases, splash water bottles, should interact with blocks and entities the way that normal water would, however, arrows of water don't follow this same concept as one would expect, therefore introducing an inconsistency.

Steps to Reproduce:

1. Obtain a bow and give yourself some arrows of water by using the command provided below.

   /give @s minecraft:tipped_arrow[minecraft:potion_contents={potion:"minecraft:water"}]

2. Summon a creeper that's on fire by using the command provided below.

   /summon minecraft:creeper ~1 ~ ~1 {NoAI:1b,Fire:999s}

3. Shoot the creeper using the bow and arrows of water.
4. Take note as to whether or not the creeper is extinguished upon being hit by the arrows of water.

Observed Behavior:

Burning blocks and entities aren't extinguished.

Expected Behavior:

Burning blocks and entities would be extinguished, following the behavior of how splash water bottles interact with blocks and entities.