Input Lag

Hi, so I am having an issue when in some games I have input lag. Sometimes the first game when I start league is fine, everything is responding super quick and I can land all my skillshots, but then i head into another game and I feel 1 second behind on all my inputs. Fps is always above 300 and my ping is never higher than 40. I have a 1080ti with i7 700k. I have no clue how one game can be so smooth and the next so slow and sluggish there is no fps drop but only response rate type of lag it's weird. If anyone can help or has the same issue please post here to let people know.