[MC-305378] Skeletons will no longer charge their bows if the CustomName is continuously changed

Skeletons interrupt the loading of their bows when their CustomName is changed using the /data command.

I noticed this behavior after programming a datapack where a mob's current health is displayed as hearts in the CustomName. To make this possible, the CustomName is set every tick. As a result, skeletons will follow a player but won't attack them with their bows.

I also reproduced this with a simple setup (see the YouTube video or the Video attached). I used the command execute as @e[type=minecraft:skeleton] run data merge entity @s {CustomNameVisible:1b,CustomName:"indic-1"} (with indic-2) to repeatedly switch the CustomName of skeletons back and forth. It can be observed that the skeletons interrupt the loading of their bows every time the CustomName is changed. I then activated a repeating command block that permanently (every tick) changes the skeletons' custom names using the command execute as @e[type=minecraft:skeleton] run data modify entity @s CustomName set from entity @s Health. This results in the same behavior I observed with the data pack.

This behavior affects not only skeletons, but also Strays and Parched.

YouTube Link: https://youtu.be/3qp_bWV6R6I or Video attached.

Environment

Java Edition
Minecraft Launcher
Version: 1.21.11

Linked issues

relates to 1

MC-274426 Continuously altering the data of a mob makes that mob unable to turn its head left and right and will make the lead unbreakable if that mob was leashed Open

Attachments

World.zip

Comments 3

marbrueck 2026-01-01T04:14:41Z

Here is an excerpt from my datapack code, which adjusts the CustomName every tick, based on their health.

execute if score @s mh.mobhealth matches 1 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/half"}]}
execute if score @s mh.mobhealth matches 2 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/full"}]}
execute if score @s mh.mobhealth matches 3 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/full"},{"atlas":"minecraft:gui","sprite":"hud/heart/half"}]}

execute if score @s mh.mobhealth matches 1 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/half"}]}
execute if score @s mh.mobhealth matches 2 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/full"}]}
execute if score @s mh.mobhealth matches 3 run data merge entity @s {CustomName:[{"atlas":"minecraft:gui","sprite":"hud/heart/full"},{"atlas":"minecraft:gui","sprite":"hud/heart/half"}]}

[MOD] Greymagic27 2026-01-01T12:16:35Z

Please attach the world/strucure file and datapack so this can be more easily reproduced

marbrueck 2026-01-01T19:41:45Z

This is the world in which I reproduced the behavior. The data pack is also present and just needs to be activated.

[media]