Hello, I have been having this problem two days after season 9 updates. When I enter the game everything is fine for the first 5mins, but there are 2-4minutes of the game where abilities lag (Along with Tab button) I can use my mouse to cast abilities normally while using them on the keyboard makes it lag and have a delay after casting (I press E, it takes a second or two to show me the aim) If I press tab more than one time, or press it 10 times, it'll show the champions info items etc 10 times like a lag. (My ping and FPS are fine) This lasts for two minutes and then it goes back to normal.
It only comes at early game 6:00-9:00 minutes. I have reinstalled the game as well, still have the same problem.
It is my first time posting I hope I did everything right.
Thank you for your time!