Malzahar ultimate bugs and issues

At first I wasn't going to bother but I have had this happen to me multiple times now and it's getting really annoying. Multiple times I have had issues with Malzahars ultimate where if I press R when my opponent is just in range they have a split second to walk just outside of its range and my ult will be canceled and go on cool down yet the sound file will trigger for a second telling me that I cast my ultimate.

I have also had issues with marksmen, this doesn't happen often but sometimes if I ult a marksman just when they auto attack me they can attack me again WHEN THE ULT IS BEING CHANNELD. I will say again that this does not happen often and has happen maybe 5 times to me since season 2. But boy does it get me salty when it does happen.

I want to say that there are a few more bugs with his ultimate but I do believe it's the queing system thats screwing up Malzahars ultimate (the in game queing system not the queing up for a match system)