What's up guys, can you please explain something to me?

How is it possible to get banned for 3 days after getting reported by one player in a match? I've fallen under 4k behavior and I've been slowly getting up, not getting reported, which is very hard considering the people who play there.

So my last 15 matches i got 13 clean and 2 games i got reported by one player. I get green conduct summary and my behavior goes up. Somehow though, I get banned for 3 days. What's the reason? The conduct clearly states 86% of players have a low report rate like me. It also clearly says that an automated low priority is given when a player recieves more reports than approx. 95% of players. So this is clearly not the case, I got banned after one guy placed one report on me in my last game and my behavior score went up. How is this possible?

ID: https://steamcommunity.com/id/supenoc

BTW I also recieved a ban for account sharing or other matchmaking abuse about a month or two ago, which was also completely unwarranted, since nobody else ever used this account and as well as this time, I didn't have more than 1-2 reports in 15 games. I brushed it off last time but this time I really want to understand, why am I getting banned without reports and my behavior going up?

Thanks for reply.