Did riot ever acknowledged the fps issues?

I've had this problem when game becomes increasingly more stuttery the longer you play since I got the access last month. I've seen some people say they've had this problem since alpha labs. I also don't remember ever seeing anything from riot about this problem. Am I just clueless or did they actually never said anything about this issue? I really like the game but being basically forced into restarting my pc after like 5-7 matches got old really fast. Feels bad missing out on the early honeymoon phase when meta is not completely figured out and there is a wide range of players to play because game doesn't work properly for me