Lag spikes

Ever since the update I am experiencing lag spikes They always occur every 10s or so and my ping goes from ~30ms to ~300/400ms for about 1s and then it goes back again. But my screen freezes for this 1s. It is just latency changes. The fps seems to remain the same.

I thought it would be my internet, but i have checked pinging other ip addresses and it seems to be normal. It happens only with League.

Is anyone else having the same issue? And anyone knows how to fix it?