Ranked LP bug

I just reached 100 LP in Silver 3 and I got a free win in my promos because it's the second time I reached 100 LP. I lost the first game, nothing weird yet.. and when I lost the second one, it showed me I lost 13 LP and I remained with 66 LP. Please fix this bug. It makes no sense. I really want my LP back. I mean, I expected to lose no more than 20 LP, but to get from promo to 66 LP it's absurd.