Where has my LP gone??

I recently won my promos to get into silver 1. First game in the league I won, and it gave me +22 LP. However, it said the resulting LP was only 19?? I looked up ways LP could be lost and found that queue dodging loses 3, but that didn't make sense because I'd never dodged a queue this season, although someone on my team had before I started that game. Without thinking too much of it, I played another game and lost -17, bringing me down to 2. My next game, someone queue dodged again, then I won +21, but resulted in 21 LP...

Do I personally lose 3 LP when someone else on my team queue dodges? If not, where the heck is all my LP going??