Banning and champion select interface freeze sometimes and causing unintentional dodges.

In the recently a couple of weeks, I experienced this unusual situation. Sometimes when I was in the process of banning or champion select, the interface just froze when someone else was banning or selecting a champion. After the banning or champion select time was up, the count down remained 0 for 30 seconds or even longer, then the game came back as there was a super lag. When it happened first time, I thought it was lag, and I asked my teammates if they experienced the same situation, and they said everything was okay and nothing happened to them. As this problem continue showing up(so far it has happened for 8-10 times), I realize that this is not lag or my own internet problem because I've never heard that there is internet lag can last for 30 seconds or even 1 minute. I am from New Jersey and my ping range is usually between 30-50. This problem have caused some unintentionally dodges. I really hope someone can help me to solve it.