Rengar sometimes doesn't jump while ulted

Hi, I've been playing Rengar for a while and I have seen that sometimes when ulted the character just won't jump, I linked 1 clip of one game and you can see that when I tried to hit the nexus, my ultimate went down and I didn't jump. I literally did nothing else than pressing Q and right click to hit the Nexus. This has happened to me a lot but I always thought it was my bad because I used W or E before the jump could go off, but with this example it's pretty clear that it wasn't my fault.

Edit: The audio is wrong, I don't know what went wrong