BUG* Champion select lock in issue

I am positive that my internet is not the issue, because never in my games I dc or lag. In almost every champion select there randomly is 8 second window where I cannot do anything. Sometimes it comes when it is my turn to pick and I can not lock in and I get cooldown and lose lp. It did not annoy for the first times but now it has been going on for a few months. Anyone else with same issue or any clue what could cause this issue? I have tried to fix the client and it did not work.