Mouse and Keyboard Bug since patch 6.9

During the game, sometimes, I can't press any button or I can't move on the map with my mouse. it lasts 5 seconde and then, if I clicked (for example) flash, I will flash 5 sec later. It's not a connection problem because when I have these lags, my ping is 25. Some people have the same problem as me and I saw on the forum that people had the same problem after the patch 5.22 (last season).
Hope we can find a solution because it sad to play league of legends when you can't move during 5 sec. [SORRY FOR MY ENGLISH][zombie-nunu-tears]