Malzahar E disappearing [Gameplay]

I've been running into a bug rather consistently with Malzahar. When I cast E on a minion right as it is about to die the Ability goes on CD but the spell doesn't resolve or bounce to a new target. I avoid casting at minions about to die so it doesn't happen but every now and then I get my timing wrong and it is increasingly frustrating.

To reproduce; attempt to cast E at a minion right before it dies/as it is dying. The Ability should go on CD but the dot doesn't appear or bounce to a new target. Not really a step by step process and hard to catch with a screen shot.