So the problem is as follows:
Whenever you change any nbt-tag of a Slime its health reverts to his max health.
Steps to reproduce:
summon in a slime with at least size 1 (since size 0 dies after one hit)
use "/entitydata @e[type=Slime] {}" and search for the health tag
hit it once
> check again and its health went downnow change any nbt-tag like CustomName with for example "/entitydata @e[type=Slime] {CustomName:"test"}
> the command displays correct health but if you test it again with the empty brackets {} it will show you the slimes max health, meaning it reseted
Tested with other mobs (Spider, Skeleton, Pig) and none had this problem
Related issues
is duplicated by
Comments


Confirmed.

Occurs in 1.9 as well.

Confirmed for 1.10-pre1

its health resets to max even when relog.

The bug with the Health Tag resetting itself is fixed.
BUT another bug concerning pretty much the same topic revealed itself by that:
Here is a the new bug report: MC-106711
the "other" was kinda wrong, because setting the health results in a health reset as well