Dodgy slowness potion effect on mobs

Encountered the same issue. I can't get slowness to work with /summon. I can tell I have the syntax right, because on the same mob I've got Resistance 5, making it invincible, and that's working fine. But slowness and speed don't seem to have any effect.

/summon Skeleton ~-2 ~1 ~ {CustomName:"Skelly Tim", CustomNameVisible:1, Equipment:[{id: 340,tag:{ench:[{id:16,lvl:-5}]}}], ActiveEffects:[{Id:2,Amplifier:5,Duration:9999999},{Id:11,Amplifier:5,Duration:9999999}]}

Is this still a concern in the current Minecraft version 1.7.2 / Launcher version 1.3.4 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

just ran into this in 1.7.2, launcher 1.3.4. It slowness affected mobs in the 1.7 snapshots, but for some reason it doesn’t anymore :/

put this into a command block and ou will see a bowless skeleton walking around normally even though it has the slowness bubbles.
/summon Skeleton ~ ~2 ~ {ActiveEffects:[{Id:2,Amplifier:6,Duration:2000,Ambient:0}]}

EDIT: As of 13w49a, launcher 1.3.6, it affects all mobs, and not just new ai ones like I previously thought.

still present in 1.7.4, launcher 1.3.7

this is pure logic, mobs are designed to not be affected by slowness etc. , try attributes they do work

ok as of 1.7.4, launcher 1.3.7 slowness seems to affect mobs via potions but not /summon. Weird. Could someone good at /giving custom potions to themselves confirm this? Because I don't know how, and it's hard to tell for sure with the vanilla slowness 1 pots.

Forward resolved to MC-32575 since there are already some other duplicates.