Picture freeze

Hi Having one problem that leads to few. Playing in EUNE. WIndows 10. It happens ingame only. Picture freezes, can't do nothing. Can't alt tab, or ctrl alt delete. Have to hold the power button for a restart. After the restart i open lol client, and it's region has been changed to NA. While i swap it to a correct one, it starts patching for about 20 minutes. So this game is a instaloss and i have 9 reports. It happens few times in a week and is probobly the most annoying crash of my gaming life, since not only me looses but the whole team. Why does it change region and why does it need to patch so long while i havent even got to patch it to wrong one. What can i do to avoid this patching?