Morganas Black Shield doesn't stop Zoe's Sleep

Are you saying that it doesn't block Zoe's sleep from landing, or that once somebody's already been hit, you can't Black Shield them to stop them from falling asleep?

If it's the former, it's a bug. It should absolutely be stopping Zoe's sleep from landing.

If it's the latter, it's working as intended. Black Shield is not a cleanse, it blocks incoming spells. If they already got hit with the spell, Black Shield isn't going to un-hit them.

It does IF you actually block the ability before it hits.

Otherwise you're trying to block something that's already hit. That's like it hitting Yasuo and him Wing to get rid of it before it takes effect.

The spell "blocks diasbles"

Sleep is a disable.

It does not block the sleep.

It shouldn't matter when the spell hits, if the black shield is on you, it should not go through.