Malzahar

Hey I am having a bad bug with malzahar. Ive played a ton of malzahar and since 5.13 seems his autos can sometimes not engage and get cs on minions when I know for sure that I got them. Just in my recent game my ult would not engage for certain part of the game and if it did, it would give me a 5 second cooldown sometimes when I used it. then I would have to redo it and it would work. This has only went on since 5.13 patch so hopefully it can get resolved :D