The matchmaking teams are randomly decided instead of using the built-in ranked system, where your rank is determined by a number.
As you can see here, the teams are 18-9-3-3 versus 17-19-17-13. Can you take a wild guess as to what team won? Can you also take a wild guess if the match was close or not?
So, clearly, the rank number isn’t functional since it’s not being used to balance teams. Is there a way to fix this or is this a known bug?