Single Disconnection IN EVERY GAMES

Since few days, I got a single disconnection every game I play. The disconnection happens every time between 6mins and 9mins. I've tried to turn off my firewall but it changed nothing SO I think the problem comes from LoL.

I'm gonna try to repair the client and see if something goes better. Anyone who was experiencing the same problem has manage to find a workaround?

EDIT1 : I tried to use the repair tool, but the bug is still there in RANKED. Interestingly, the bug seems not to appear in Normal Draft games. I only get a super fast little freeze and not a disconnection of about 30s-1min like in RANKED games.