I lost two games in a row, one for -16 LP and then other demoted me to Platinum II 75 LP, which means that my MMR isn't low.
I then won 9 games and lost 2.
All 9 wins are +15 LP, regardless of the fact I was gaining +22 LP before I demoted.
Both losses were -20 LP, regardless of the fact I was only losing -16 LP before I demoted.
What the fuck is going on here? At the very least, I would expect my LP gains to increase from 15 after going 9-2.