You are right, and it’s so strange. I searched a bit and am now watching a new player play ranked games against 1d players. They lost the first one and the rank went up from 11.8k or whatever it was to 10.8k. Then the second loss brought it up to 10.3k. Now it’s showing 7k in the thumbnail.
Update: three losses against 1d apparently gets you up to 10.0k.