Yasuo wind wall bug

I have encounter this bug many times in the past month... of the abilities that the wind wall should block, it does it about half the time... i have played a game against a teemo and thrown my wind wall out to block his q and it does.... but later in the game i do it again and it does not block it so i am blinded and ultimately screwed... this annoys me because sometimes when u r yas, all u can do is get a good wind wall to win a fight... if it doesn't work half the time, it is just useless... i have seen this bug (and other people have noticed it too) for about a month and nothing has been done to fix it