Zilean's Abilities bugging out

I've been playing the old timer for quite a while now and a lot of other Zilean players that I have come across seem to say the same thing. Zileans abilities can get very buggy and landing combos can become rather stressful.

In a very fast paced environment, especially with spell queuing on, I have somehow been able to cast Q W Q, WITHOUT the first q going off, but the W resetting the ability so i am able to cast q again. If anyone knows how the current Zil works, you would know you cannot cast W while Q and E are off cooldown.

Another glitch seems to be whenever I try to cast my passive on a player who is ready, it can take several clicks before the ability realises it is in range and able to cast AND occasionally doesn't cast at all and instead casts Zileans E. I have tested this a few times and the circumstances seem to be random.

I'm not sure if it's relevant, but it seems to have worsened around the time they implemented the patch to make Alistars combos easier to land, but maybe I'm just imagining things.