Rank Game loss of LP without playing Rank

So on sunday I played 2 rank games when I finished I ended up with 51 LP. Later that night I played 5ARAM games in a row so I could get that IP party boost. I lost all those games. When I checked last night my Rank games for LP went from 51 to 48. Is this even possible?

I can lose Rank LP for playing ARAM. I'm not that upset because it is just 4 points. But im just saying it's confusing me.