LOL auto change region to North America when I turned it on

Recently, LOL have lots of bugs like treadmill walking , attempting to reconnect,... etc ( high MS that they've never happened before this patch). Specially, they automatically change region to North America and auto loading America patch , when I downloaded EUW patch, I don't know why ? (my account in EUW server, it used to stayed in America, due to high ms I had to move account to EUW)