"minecraft.killed:minecraft.<ENTITY>" doesn't increase when entities are killed through being damaged by other sources after being attacked by the player

The Bug:

"minecraft.killed:minecraft.<ENTITY>" doesn't increase when entities are killed through being damaged by other sources after being attacked by the player.

Steps to Reproduce:

1. Create a scoreboard objective for tracking when you kill a husk and set it to display on the sidebar by using the commands provided below. 

   /scoreboard objectives add KillHusk minecraft.killed:minecraft.husk

   /scoreboard objectives setdisplay sidebar KillHusk

2. Summon a husk, kill it normally and take note of how the scoreboard increases.
3. Build the setup as shown in the attachment below. setup.png
4. Summon a husk on the diamond block that has low health by using the command provided below.

   /summon minecraft:husk ~ ~ ~ {Health:2f}

5. Punch the husk into the fire and allow it to die from burning.
6. Take note as whether or not "minecraft.killed:minecraft.<ENTITY>" doesn't increase when entities are killed through being damaged by other sources after being attacked by the player.

Observed Behavior:

"minecraft.killed:minecraft.<ENTITY>" doesn't increase when entities are killed through being damaged by other sources after being attacked by the player.

Expected Behavior:

"minecraft.killed:minecraft.<ENTITY>" would increase when entities are killed through being damaged by other sources after being attacked by the player.