Unknown error caused me to get less LP?

I just finished a game, and this season I have been averaging about 23 lp per game or so. The game ended and an unknown error popped up and I had to click ok about four times before the error screen went away, then I noticed I only got 11 lp, and the rest of the lobby that won also got 12 or just 11. It was odd because the players in the lobby were just about my level or even higher when it comes to mmr. Anyone else got this issue? I wish I had that lp i would only be 1 game away from my promos again.