[CLIENT] Said I had negative LP in Bronze IV

I was playing yesterday, and I won my placements to get out of Bronze V. I was happy, I'm getting better. I queued up for another game. Got Jungle, but Mid wanted to switch, so we ended up switching. So we get into the game, and after a couple minutes, they remade the game. Shaco was AFK. I did what I always do when someone is AFK: I reported them. Then I looked on the very top, where it says your LP and rank. It said I was at -20 LP. Which was strange, as I just won my placements and that was my first game in Bronze IV. I noticed it happening when I was in Bronze V, but I thought that was just how it was since that's the lowest rank. But negative LP in Bronze IV? Doesn't seem right to me.