Lee Sin AA after second Q while being stunned

Hey,

so this happened in a Xerath game of mine today. While Lee was dashing towards me with his second Q instance, I stunned him midway but after arriving he was still able to AA me while he was still stunned. Xerath already is a glass canon so this would be great if it would be fixed. Also I guess this always happens with a stunned Lee Sin and his second Q. Also got a replay of that but dont know how to post it here, but it should be able to see in a custom or smth.