this just happened to me as well. I crashed during the loadscreen which happens occasionally to me, but i reconnected before the first round even started and it marked me as abandoned despite reconnecting and winning the game. I am banned for 6 hours rn.
Here is my match id: 58918060
I know its impossible to detect, but ive been playing this game for a long time at this point. I have over 1k hours and I NEVER abandon. I have never once willingly left a game in the middle of it. All of my game bands have been from crashing or bugs. I would appreciate a reset on my bans once a month or something. I have no idea how often they clear them, but i really hate being unable to play my favorite game because it has an issue with crashing on occasion and it often doesnt even impact the result of the match by the time i reconnect.