The Bug

When using the command /summon and spawning a mob in with a status effect applied, 4 status effects will not function properly. The status effects that do not work that I have tested was: Speed , Slowness , Strength , Weakness. The other effects do work still.

To Recreate It

Use the /summon command and summon a mob with any of the 4 status effect attached to it.

/summon minecraft:mob ~ ~ ~ {ActiveEffects:[

{Id:*any of the 4 effects's ids*,Amplifier:1,Duration:300}

]}

Here is an example: /summon minecraft:spider ~ ~ ~ {ActiveEffects:[

{Id:1,Amplifier:1,Duration:3000}

]}

 

This command is supposed to give a spider Speed 2, but it does not make the spider any faster than a normal spider.