First reported in MC-248658, but this was created in the experimental snapshot. [Helper] markderickson said to create a new report if a new one doesn't currently exist for a current version. The only report I could find was MC-248658, so I created this post.
This might be intended, since the Warden isn't something players are meant to kill. I just created it in case it isn't intentional.
The bug:
The Warden doesn't count towards "minecraft:adventure/kill_a_mob" advancement and most likely also doesn't count towards "minecraft:adventure/kill_all_mobs" advancement.
Steps to reproduce
/advancement revoke @s everything (just to make sure you haven't gotten the advancement already)
/summon warden
/data modify entity @e[type=warden,limit=1] Health set value 1
/gamemode survival (if you aren't in survival already)
Punch the warden. It should die in one hit because its health is 1
Observed Results
The player doesn't get the advancement
Expected Result
The player should get the advancement
I think this because most people will never kill the warden without killing, let’s say, a zombie, before they even find an ancient city (which are incredibly rare).