Zephyr/assassin negates Blitz/Assassin abilities

I've run into an issue multiple times now where my Blitzcrank or my assassin has no target because the target becomes untargetable due to that target either being an assassin or because my own Zephyr throws them up in the air. My blitz/assassin will then sit in their space, effectively stunned, for a few seconds before finally moving up to auto attack without using their ability. After engaging, they may use their ability later (assuming they're still alive by then).