Placement bug

I had 6/10 placements left.I played a ranked game today and when I finished it it told me :"Placements complete" or something when I had 6/10 before that game so I would have had 3 more placements left now and I would go a little higher in ranked.Btw I was bronze 1 when I was 6/10 ,after that game I went up in silver 4 idk if it has to do with something.If it's not a bug please explain what happened