This has happened a few times over the last couple days so I see it as recurrent. Sometimes at the end of the countdown for game start, you get an error and get booted out of the game. If you refresh, you see that the match didn’t start but shows up in your history as a loss.
i.e. match id t3b9rYDEm a few minutes ago for which a replay doesn’t exist https://curvefever.pro/56/replay/t3b9rYDEm because there was no match but still shows as a loss (and -23 in this case).