The Bug

When a patrol leader is killed by a tipped arrow of harming if the death is a result of the status effect rather than the arrow itself the kill will not be counted for the player. This appears to be the case for all mobs as the statistics page does not count kills of this manner towards the number displayed and neither do scoreboards. This isn't the case for the normal arrow or the splash potion of harming so it doesn't seem to be intentional behavior.

Steps to Reproduce

• Obtain a bow and some arrows of harming.
• Summon a pillager captain. (A command block is required in order to execute this command).

  /summon minecraft:pillager ~ ~ ~ {Health:8f,PatrolLeader:1b,HandItems:[{id:"minecraft:crossbow",Count:1b},{}],ArmorItems:[{},{},{},{id:"minecraft:white_banner",Count:1b,tag:{HideFlags:32,BlockEntityTag:{Patterns:[{Pattern:"mr",Color:9},{Pattern:"bs",Color:8},{Pattern:"cs",Color:7},{Pattern:"bo",Color:8},{Pattern:"ms",Color:15},{Pattern:"hh",Color:8},{Pattern:"mc",Color:8},{Pattern:"bo",Color:15}],id:"minecraft:banner"},display:{Name:'{"color":"gold","translate":"block.minecraft.ominous_banner"}'}}}]}
  

• Shoot and kill the pillager using your bow and arrows of harming.
• Take note as to whether or not the bad omen effect sometimes isn't granted when pillager captains die from the effects of tipped arrows.

Observed Behavior

The bad omen effect sometimes isn't granted when pillager captains die from the effects of tipped arrows.

Expected Behavior

The bad omen effect would always be granted when pillager captains die from the effects of tipped arrows.