Creeper explosion in water do not kill mobs

What Should Happen:

When mobs are near a creeper explosion they should get damaged and/or killed even in water.

What Happened Instead:

The mob near the creeper explosion in water appears to be damaged but cannot die from the explosion. This of course does not happen if they are both on land.

Steps to Reproduce:

-spawn a creeper and another mob in the same space.

-place water where they are standing.

-summon lightning near them to turn the creeper into a charged creeper.

(optional) -decrease the health of the other mob.

-ignite the creeper.

You'll notice that the mob appears to be damaged, but it should be dead because the damage dealt by the creeper increases the closer it is to a mob. So the husk should be dead as it is in the same spot as the creeper. This bug prevents players from farming mob heads, please fix this.

(I searched for a duplicate but didn't find any. This issue has been around for a long time but I just thought it got fixed at some point, but turns out it's still here.)